Prepare for compat-framework support

- Create a Context for the system server
- Add the target SDK level to RavenwoodConfig
- Allow PropertyInvalidatedCache sysprops
- Copy StatsD classes, until we get a proper support
- Copy Compatibility and some annotations from libcore
- Keep FrameworkStatsLog

Flag: EXEMPT host test change only
Bug: 292141694
Test: $ANDROID_BUILD_TOP/frameworks/base/ravenwood/scripts/run-ravenwood-tests.sh
Change-Id: Ib572d1b25c47c693b4969d12490e593dc5f48eb1

15 files changed, 2172 insertions, 1 deletions

diff --git a/ravenwood/Android.bp b/ravenwood/Android.bp
index d9182010c1cb..ff2abd275f83 100644
--- a/ravenwood/Android.bp
+++ b/ravenwood/Android.bp
@@ -100,6 +100,9 @@ java_library_host {
     srcs: [
         "runtime-helper-src/libcore-fake/**/*.java",
     ],
+    libs: [
+        "app-compat-annotations",
+    ],
     static_libs: [
         "ravenwood-runtime-common",
     ],
@@ -121,6 +124,7 @@ java_library {
     ],
     static_libs: [
         "ravenwood-runtime-common",
+        "androidx.annotation_annotation",
     ],
     libs: [
         "framework-minus-apex.ravenwood",
diff --git a/ravenwood/junit-impl-src/android/platform/test/ravenwood/RavenwoodConfigState.java b/ravenwood/junit-impl-src/android/platform/test/ravenwood/RavenwoodConfigState.java
index 3535cb2b1b79..870a10a1f57e 100644
--- a/ravenwood/junit-impl-src/android/platform/test/ravenwood/RavenwoodConfigState.java
+++ b/ravenwood/junit-impl-src/android/platform/test/ravenwood/RavenwoodConfigState.java
@@ -42,6 +42,10 @@ public class RavenwoodConfigState {
 
     private final RavenwoodConfig mConfig;
 
+    // TODO: Move the other contexts from RavenwoodConfig to here too? They're used by
+    // RavenwoodRule too, but RavenwoodRule can probably use InstrumentationRegistry?
+    RavenwoodContext mSystemServerContext;
+
     public RavenwoodConfigState(RavenwoodConfig config) {
         mConfig = config;
     }
diff --git a/ravenwood/junit-impl-src/android/platform/test/ravenwood/RavenwoodRuntimeEnvironmentController.java b/ravenwood/junit-impl-src/android/platform/test/ravenwood/RavenwoodRuntimeEnvironmentController.java
index 9a145cb93811..c2806daf99a1 100644
--- a/ravenwood/junit-impl-src/android/platform/test/ravenwood/RavenwoodRuntimeEnvironmentController.java
+++ b/ravenwood/junit-impl-src/android/platform/test/ravenwood/RavenwoodRuntimeEnvironmentController.java
@@ -16,6 +16,8 @@
 
 package android.platform.test.ravenwood;
 
+import static android.platform.test.ravenwood.RavenwoodSystemServer.ANDROID_PACKAGE_NAME;
+
 import static com.android.ravenwood.common.RavenwoodCommonUtils.RAVENWOOD_INST_RESOURCE_APK;
 import static com.android.ravenwood.common.RavenwoodCommonUtils.RAVENWOOD_RESOURCE_APK;
 import static com.android.ravenwood.common.RavenwoodCommonUtils.RAVENWOOD_VERBOSE_LOGGING;
@@ -267,6 +269,13 @@ public class RavenwoodRuntimeEnvironmentController {
         config.mInstContext = instContext;
         config.mTargetContext = targetContext;
 
+        final Supplier<Resources> systemResourcesLoader = () -> {
+            return config.mState.loadResources(null);
+        };
+
+        config.mState.mSystemServerContext =
+                new RavenwoodContext(ANDROID_PACKAGE_NAME, main, systemResourcesLoader);
+
         // Prepare other fields.
         config.mInstrumentation = new Instrumentation();
         config.mInstrumentation.basicInit(instContext, targetContext, createMockUiAutomation());
@@ -314,6 +323,9 @@ public class RavenwoodRuntimeEnvironmentController {
             ((RavenwoodContext) config.mTargetContext).cleanUp();
             config.mTargetContext = null;
         }
+        if (config.mState.mSystemServerContext != null) {
+            config.mState.mSystemServerContext.cleanUp();
+        }
 
         Looper.getMainLooper().quit();
         Looper.clearMainLooperForTest();
diff --git a/ravenwood/junit-impl-src/android/platform/test/ravenwood/RavenwoodSystemServer.java b/ravenwood/junit-impl-src/android/platform/test/ravenwood/RavenwoodSystemServer.java
index 3946dd8471b0..f198a08a50e3 100644
--- a/ravenwood/junit-impl-src/android/platform/test/ravenwood/RavenwoodSystemServer.java
+++ b/ravenwood/junit-impl-src/android/platform/test/ravenwood/RavenwoodSystemServer.java
@@ -33,6 +33,9 @@ import java.util.List;
 import java.util.Set;
 
 public class RavenwoodSystemServer {
+
+    static final String ANDROID_PACKAGE_NAME = "android";
+
     /**
      * Set of services that we know how to provide under Ravenwood. We keep this set distinct
      * from {@code com.android.server.SystemServer} to give us the ability to choose either
@@ -67,7 +70,7 @@ public class RavenwoodSystemServer {
 
         sStartedServices = new ArraySet<>();
         sTimings = new TimingsTraceAndSlog();
-        sServiceManager = new SystemServiceManager(config.mInstContext);
+        sServiceManager = new SystemServiceManager(config.mState.mSystemServerContext);
         sServiceManager.setStartInfo(false,
                 SystemClock.elapsedRealtime(),
                 SystemClock.uptimeMillis());
diff --git a/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodConfig.java b/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodConfig.java
index 1f6e11dd5cf2..37b0abcceede 100644
--- a/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodConfig.java
+++ b/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodConfig.java
@@ -67,6 +67,7 @@ public final class RavenwoodConfig {
     String mTargetPackageName;
 
     int mMinSdkLevel;
+    int mTargetSdkLevel;
 
     boolean mProvideMainThread = false;
 
@@ -150,6 +151,14 @@ public final class RavenwoodConfig {
         }
 
         /**
+         * Configure the target SDK level of the test.
+         */
+        public Builder setTargetSdkLevel(int sdkLevel) {
+            mConfig.mTargetSdkLevel = sdkLevel;
+            return this;
+        }
+
+        /**
          * Configure a "main" thread to be available for the duration of the test, as defined
          * by {@code Looper.getMainLooper()}. Has no effect on non-Ravenwood environments.
          *
diff --git a/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodSystemProperties.java b/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodSystemProperties.java
index ced151927fdc..9bc45bee1775 100644
--- a/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodSystemProperties.java
+++ b/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodSystemProperties.java
@@ -146,6 +146,9 @@ public class RavenwoodSystemProperties {
         if (root.startsWith("soc.")) return true;
         if (root.startsWith("system.")) return true;
 
+        // For PropertyInvalidatedCache
+        if (root.startsWith("cache_key.")) return true;
+
         switch (key) {
             case "gsm.version.baseband":
             case "no.such.thing":
@@ -170,6 +173,9 @@ public class RavenwoodSystemProperties {
 
         if (root.startsWith("debug.")) return true;
 
+        // For PropertyInvalidatedCache
+        if (root.startsWith("cache_key.")) return true;
+
         return mKeyWritable.contains(key);
     }
 
diff --git a/ravenwood/runtime-helper-src/framework/android/util/StatsEvent.java b/ravenwood/runtime-helper-src/framework/android/util/StatsEvent.java
new file mode 100644
index 000000000000..1e3b3fcd733f
--- /dev/null
+++ b/ravenwood/runtime-helper-src/framework/android/util/StatsEvent.java
@@ -0,0 +1,1035 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.util;
+
+// [ravenwood] This is an exact copy from StatsD, until we make StatsD available on Ravenwood.
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.annotation.SystemApi;
+import android.os.Build;
+import android.os.SystemClock;
+
+import androidx.annotation.RequiresApi;
+
+import com.android.internal.annotations.GuardedBy;
+import com.android.internal.annotations.VisibleForTesting;
+
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+
+/**
+ * StatsEvent builds and stores the buffer sent over the statsd socket.
+ * This class defines and encapsulates the socket protocol.
+ *
+ * <p>Usage:</p>
+ * <pre>
+ *      // Pushed event
+ *      StatsEvent statsEvent = StatsEvent.newBuilder()
+ *          .setAtomId(atomId)
+ *          .writeBoolean(false)
+ *          .writeString("annotated String field")
+ *          .addBooleanAnnotation(annotationId, true)
+ *          .usePooledBuffer()
+ *          .build();
+ *      StatsLog.write(statsEvent);
+ *
+ *      // Pulled event
+ *      StatsEvent statsEvent = StatsEvent.newBuilder()
+ *          .setAtomId(atomId)
+ *          .writeBoolean(false)
+ *          .writeString("annotated String field")
+ *          .addBooleanAnnotation(annotationId, true)
+ *          .build();
+ * </pre>
+ * @hide
+ **/
+@SystemApi
+public final class StatsEvent {
+    // Type Ids.
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final byte TYPE_INT = 0x00;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final byte TYPE_LONG = 0x01;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final byte TYPE_STRING = 0x02;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final byte TYPE_LIST = 0x03;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final byte TYPE_FLOAT = 0x04;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final byte TYPE_BOOLEAN = 0x05;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final byte TYPE_BYTE_ARRAY = 0x06;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final byte TYPE_OBJECT = 0x07;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final byte TYPE_KEY_VALUE_PAIRS = 0x08;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final byte TYPE_ATTRIBUTION_CHAIN = 0x09;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final byte TYPE_ERRORS = 0x0F;
+
+    // Error flags.
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final int ERROR_NO_TIMESTAMP = 0x1;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final int ERROR_NO_ATOM_ID = 0x2;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final int ERROR_OVERFLOW = 0x4;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final int ERROR_ATTRIBUTION_CHAIN_TOO_LONG = 0x8;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final int ERROR_TOO_MANY_KEY_VALUE_PAIRS = 0x10;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final int ERROR_ANNOTATION_DOES_NOT_FOLLOW_FIELD = 0x20;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final int ERROR_INVALID_ANNOTATION_ID = 0x40;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final int ERROR_ANNOTATION_ID_TOO_LARGE = 0x80;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final int ERROR_TOO_MANY_ANNOTATIONS = 0x100;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final int ERROR_TOO_MANY_FIELDS = 0x200;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final int ERROR_ATTRIBUTION_UIDS_TAGS_SIZES_NOT_EQUAL = 0x1000;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final int ERROR_ATOM_ID_INVALID_POSITION = 0x2000;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting public static final int ERROR_LIST_TOO_LONG = 0x4000;
+
+    // Size limits.
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final int MAX_ANNOTATION_COUNT = 15;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final int MAX_ATTRIBUTION_NODES = 127;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final int MAX_NUM_ELEMENTS = 127;
+
+    /**
+     * @hide
+     **/
+    @VisibleForTesting
+    public static final int MAX_KEY_VALUE_PAIRS = 127;
+
+    private static final int LOGGER_ENTRY_MAX_PAYLOAD = 4068;
+
+    // Max payload size is 4 bytes less as 4 bytes are reserved for statsEventTag.
+    // See android_util_StatsLog.cpp.
+    private static final int MAX_PUSH_PAYLOAD_SIZE = LOGGER_ENTRY_MAX_PAYLOAD - 4;
+
+    private static final int MAX_PULL_PAYLOAD_SIZE = 50 * 1024; // 50 KB
+
+    private final int mAtomId;
+    private final byte[] mPayload;
+    private Buffer mBuffer;
+    private final int mNumBytes;
+
+    private StatsEvent(final int atomId, @Nullable final Buffer buffer,
+            @NonNull final byte[] payload, final int numBytes) {
+        mAtomId = atomId;
+        mBuffer = buffer;
+        mPayload = payload;
+        mNumBytes = numBytes;
+    }
+
+    /**
+     * Returns a new StatsEvent.Builder for building StatsEvent object.
+     **/
+    @NonNull
+    public static Builder newBuilder() {
+        return new Builder(Buffer.obtain());
+    }
+
+    /**
+     * Get the atom Id of the atom encoded in this StatsEvent object.
+     *
+     * @hide
+     **/
+    public int getAtomId() {
+        return mAtomId;
+    }
+
+    /**
+     * Get the byte array that contains the encoded payload that can be sent to statsd.
+     *
+     * @hide
+     **/
+    @NonNull
+    public byte[] getBytes() {
+        return mPayload;
+    }
+
+    /**
+     * Get the number of bytes used to encode the StatsEvent payload.
+     *
+     * @hide
+     **/
+    public int getNumBytes() {
+        return mNumBytes;
+    }
+
+    /**
+     * Recycle resources used by this StatsEvent object.
+     * No actions should be taken on this StatsEvent after release() is called.
+     *
+     * @hide
+     **/
+    public void release() {
+        if (mBuffer != null) {
+            mBuffer.release();
+            mBuffer = null;
+        }
+    }
+
+    /**
+     * Builder for constructing a StatsEvent object.
+     *
+     * <p>This class defines and encapsulates the socket encoding for the
+     *buffer. The write methods must be called in the same order as the order of
+     *fields in the atom definition.</p>
+     *
+     * <p>setAtomId() must be called immediately after
+     *StatsEvent.newBuilder().</p>
+     *
+     * <p>Example:</p>
+     * <pre>
+     *     // Atom definition.
+     *     message MyAtom {
+     *         optional int32 field1 = 1;
+     *         optional int64 field2 = 2;
+     *         optional string field3 = 3 [(annotation1) = true];
+     *         optional repeated int32 field4 = 4;
+     *     }
+     *
+     *     // StatsEvent construction for pushed event.
+     *     StatsEvent.newBuilder()
+     *     StatsEvent statsEvent = StatsEvent.newBuilder()
+     *         .setAtomId(atomId)
+     *         .writeInt(3) // field1
+     *         .writeLong(8L) // field2
+     *         .writeString("foo") // field 3
+     *         .addBooleanAnnotation(annotation1Id, true)
+     *         .writeIntArray({ 1, 2, 3 });
+     *         .usePooledBuffer()
+     *         .build();
+     *
+     *     // StatsEvent construction for pulled event.
+     *     StatsEvent.newBuilder()
+     *     StatsEvent statsEvent = StatsEvent.newBuilder()
+     *         .setAtomId(atomId)
+     *         .writeInt(3) // field1
+     *         .writeLong(8L) // field2
+     *         .writeString("foo") // field 3
+     *         .addBooleanAnnotation(annotation1Id, true)
+     *         .writeIntArray({ 1, 2, 3 });
+     *         .build();
+     * </pre>
+     **/
+    public static final class Builder {
+        // Fixed positions.
+        private static final int POS_NUM_ELEMENTS = 1;
+        private static final int POS_TIMESTAMP_NS = POS_NUM_ELEMENTS + Byte.BYTES;
+        private static final int POS_ATOM_ID = POS_TIMESTAMP_NS + Byte.BYTES + Long.BYTES;
+
+        private final Buffer mBuffer;
+        private long mTimestampNs;
+        private int mAtomId;
+        private byte mCurrentAnnotationCount;
+        private int mPos;
+        private int mPosLastField;
+        private byte mLastType;
+        private int mNumElements;
+        private int mErrorMask;
+        private boolean mUsePooledBuffer = false;
+
+        private Builder(final Buffer buffer) {
+            mBuffer = buffer;
+            mCurrentAnnotationCount = 0;
+            mAtomId = 0;
+            mTimestampNs = SystemClock.elapsedRealtimeNanos();
+            mNumElements = 0;
+
+            // Set mPos to 0 for writing TYPE_OBJECT at 0th position.
+            mPos = 0;
+            writeTypeId(TYPE_OBJECT);
+
+            // Write timestamp.
+            mPos = POS_TIMESTAMP_NS;
+            writeLong(mTimestampNs);
+        }
+
+        /**
+         * Sets the atom id for this StatsEvent.
+         *
+         * This should be called immediately after StatsEvent.newBuilder()
+         * and should only be called once.
+         * Not calling setAtomId will result in ERROR_NO_ATOM_ID.
+         * Calling setAtomId out of order will result in ERROR_ATOM_ID_INVALID_POSITION.
+         **/
+        @NonNull
+        public Builder setAtomId(final int atomId) {
+            if (0 == mAtomId) {
+                mAtomId = atomId;
+
+                if (1 == mNumElements) { // Only timestamp is written so far.
+                    writeInt(atomId);
+                } else {
+                    // setAtomId called out of order.
+                    mErrorMask |= ERROR_ATOM_ID_INVALID_POSITION;
+                }
+            }
+
+            return this;
+        }
+
+        /**
+         * Write a boolean field to this StatsEvent.
+         **/
+        @NonNull
+        public Builder writeBoolean(final boolean value) {
+            // Write boolean typeId byte followed by boolean byte representation.
+            writeTypeId(TYPE_BOOLEAN);
+            mPos += mBuffer.putBoolean(mPos, value);
+            mNumElements++;
+            return this;
+        }
+
+        /**
+         * Write an integer field to this StatsEvent.
+         **/
+        @NonNull
+        public Builder writeInt(final int value) {
+            // Write integer typeId byte followed by 4-byte representation of value.
+            writeTypeId(TYPE_INT);
+            mPos += mBuffer.putInt(mPos, value);
+            mNumElements++;
+            return this;
+        }
+
+        /**
+         * Write a long field to this StatsEvent.
+         **/
+        @NonNull
+        public Builder writeLong(final long value) {
+            // Write long typeId byte followed by 8-byte representation of value.
+            writeTypeId(TYPE_LONG);
+            mPos += mBuffer.putLong(mPos, value);
+            mNumElements++;
+            return this;
+        }
+
+        /**
+         * Write a float field to this StatsEvent.
+         **/
+        @NonNull
+        public Builder writeFloat(final float value) {
+            // Write float typeId byte followed by 4-byte representation of value.
+            writeTypeId(TYPE_FLOAT);
+            mPos += mBuffer.putFloat(mPos, value);
+            mNumElements++;
+            return this;
+        }
+
+        /**
+         * Write a String field to this StatsEvent.
+         **/
+        @NonNull
+        public Builder writeString(@NonNull final String value) {
+            // Write String typeId byte, followed by 4-byte representation of number of bytes
+            // in the UTF-8 encoding, followed by the actual UTF-8 byte encoding of value.
+            final byte[] valueBytes = stringToBytes(value);
+            writeByteArray(valueBytes, TYPE_STRING);
+            return this;
+        }
+
+        /**
+         * Write a byte array field to this StatsEvent.
+         **/
+        @NonNull
+        public Builder writeByteArray(@NonNull final byte[] value) {
+            // Write byte array typeId byte, followed by 4-byte representation of number of bytes
+            // in value, followed by the actual byte array.
+            writeByteArray(value, TYPE_BYTE_ARRAY);
+            return this;
+        }
+
+        private void writeByteArray(@NonNull final byte[] value, final byte typeId) {
+            writeTypeId(typeId);
+            final int numBytes = value.length;
+            mPos += mBuffer.putInt(mPos, numBytes);
+            mPos += mBuffer.putByteArray(mPos, value);
+            mNumElements++;
+        }
+
+        /**
+         * Write an attribution chain field to this StatsEvent.
+         *
+         * The sizes of uids and tags must be equal. The AttributionNode at position i is
+         * made up of uids[i] and tags[i].
+         *
+         * @param uids array of uids in the attribution nodes.
+         * @param tags array of tags in the attribution nodes.
+         **/
+        @NonNull
+        public Builder writeAttributionChain(
+                @NonNull final int[] uids, @NonNull final String[] tags) {
+            final byte numUids = (byte) uids.length;
+            final byte numTags = (byte) tags.length;
+
+            if (numUids != numTags) {
+                mErrorMask |= ERROR_ATTRIBUTION_UIDS_TAGS_SIZES_NOT_EQUAL;
+            } else if (numUids > MAX_ATTRIBUTION_NODES) {
+                mErrorMask |= ERROR_ATTRIBUTION_CHAIN_TOO_LONG;
+            } else {
+                // Write attribution chain typeId byte, followed by 1-byte representation of
+                // number of attribution nodes, followed by encoding of each attribution node.
+                writeTypeId(TYPE_ATTRIBUTION_CHAIN);
+                mPos += mBuffer.putByte(mPos, numUids);
+                for (int i = 0; i < numUids; i++) {
+                    // Each uid is encoded as 4-byte representation of its int value.
+                    mPos += mBuffer.putInt(mPos, uids[i]);
+
+                    // Each tag is encoded as 4-byte representation of number of bytes in its
+                    // UTF-8 encoding, followed by the actual UTF-8 bytes.
+                    final byte[] tagBytes = stringToBytes(tags[i]);
+                    mPos += mBuffer.putInt(mPos, tagBytes.length);
+                    mPos += mBuffer.putByteArray(mPos, tagBytes);
+                }
+                mNumElements++;
+            }
+            return this;
+        }
+
+        /**
+         * Write KeyValuePairsAtom entries to this StatsEvent.
+         *
+         * @param intMap Integer key-value pairs.
+         * @param longMap Long key-value pairs.
+         * @param stringMap String key-value pairs.
+         * @param floatMap Float key-value pairs.
+         **/
+        @NonNull
+        public Builder writeKeyValuePairs(
+                @Nullable final SparseIntArray intMap,
+                @Nullable final SparseLongArray longMap,
+                @Nullable final SparseArray<String> stringMap,
+                @Nullable final SparseArray<Float> floatMap) {
+            final int intMapSize = null == intMap ? 0 : intMap.size();
+            final int longMapSize = null == longMap ? 0 : longMap.size();
+            final int stringMapSize = null == stringMap ? 0 : stringMap.size();
+            final int floatMapSize = null == floatMap ? 0 : floatMap.size();
+            final int totalCount = intMapSize + longMapSize + stringMapSize + floatMapSize;
+
+            if (totalCount > MAX_KEY_VALUE_PAIRS) {
+                mErrorMask |= ERROR_TOO_MANY_KEY_VALUE_PAIRS;
+            } else {
+                writeTypeId(TYPE_KEY_VALUE_PAIRS);
+                mPos += mBuffer.putByte(mPos, (byte) totalCount);
+
+                for (int i = 0; i < intMapSize; i++) {
+                    final int key = intMap.keyAt(i);
+                    final int value = intMap.valueAt(i);
+                    mPos += mBuffer.putInt(mPos, key);
+                    writeTypeId(TYPE_INT);
+                    mPos += mBuffer.putInt(mPos, value);
+                }
+
+                for (int i = 0; i < longMapSize; i++) {
+                    final int key = longMap.keyAt(i);
+                    final long value = longMap.valueAt(i);
+                    mPos += mBuffer.putInt(mPos, key);
+                    writeTypeId(TYPE_LONG);
+                    mPos += mBuffer.putLong(mPos, value);
+                }
+
+                for (int i = 0; i < stringMapSize; i++) {
+                    final int key = stringMap.keyAt(i);
+                    final String value = stringMap.valueAt(i);
+                    mPos += mBuffer.putInt(mPos, key);
+                    writeTypeId(TYPE_STRING);
+                    final byte[] valueBytes = stringToBytes(value);
+                    mPos += mBuffer.putInt(mPos, valueBytes.length);
+                    mPos += mBuffer.putByteArray(mPos, valueBytes);
+                }
+
+                for (int i = 0; i < floatMapSize; i++) {
+                    final int key = floatMap.keyAt(i);
+                    final float value = floatMap.valueAt(i);
+                    mPos += mBuffer.putInt(mPos, key);
+                    writeTypeId(TYPE_FLOAT);
+                    mPos += mBuffer.putFloat(mPos, value);
+                }
+
+                mNumElements++;
+            }
+
+            return this;
+        }
+
+        /**
+         * Write a repeated boolean field to this StatsEvent.
+         *
+         * The list size must not exceed 127. Otherwise, the array isn't written
+         * to the StatsEvent and ERROR_LIST_TOO_LONG is appended to the
+         * StatsEvent errors field.
+         *
+         * @param elements array of booleans.
+         **/
+        @RequiresApi(Build.VERSION_CODES.TIRAMISU)
+        @NonNull
+        public Builder writeBooleanArray(@NonNull final boolean[] elements) {
+            final byte numElements = (byte)elements.length;
+
+            if (writeArrayInfo(numElements, TYPE_BOOLEAN)) {
+                // Write encoding of each element.
+                for (int i = 0; i < numElements; i++) {
+                    mPos += mBuffer.putBoolean(mPos, elements[i]);
+                }
+                mNumElements++;
+            }
+            return this;
+        }
+
+        /**
+         * Write a repeated int field to this StatsEvent.
+         *
+         * The list size must not exceed 127. Otherwise, the array isn't written
+         * to the StatsEvent and ERROR_LIST_TOO_LONG is appended to the
+         * StatsEvent errors field.
+         *
+         * @param elements array of ints.
+         **/
+        @RequiresApi(Build.VERSION_CODES.TIRAMISU)
+        @NonNull
+        public Builder writeIntArray(@NonNull final int[] elements) {
+            final byte numElements = (byte)elements.length;
+
+            if (writeArrayInfo(numElements, TYPE_INT)) {
+              // Write encoding of each element.
+              for (int i = 0; i < numElements; i++) {
+                mPos += mBuffer.putInt(mPos, elements[i]);
+                }
+                mNumElements++;
+            }
+            return this;
+        }
+
+        /**
+         * Write a repeated long field to this StatsEvent.
+         *
+         * The list size must not exceed 127. Otherwise, the array isn't written
+         * to the StatsEvent and ERROR_LIST_TOO_LONG is appended to the
+         * StatsEvent errors field.
+         *
+         * @param elements array of longs.
+         **/
+        @RequiresApi(Build.VERSION_CODES.TIRAMISU)
+        @NonNull
+        public Builder writeLongArray(@NonNull final long[] elements) {
+            final byte numElements = (byte)elements.length;
+
+            if (writeArrayInfo(numElements, TYPE_LONG)) {
+                // Write encoding of each element.
+                for (int i = 0; i < numElements; i++) {
+                    mPos += mBuffer.putLong(mPos, elements[i]);
+                }
+                mNumElements++;
+            }
+            return this;
+        }
+
+        /**
+         * Write a repeated float field to this StatsEvent.
+         *
+         * The list size must not exceed 127. Otherwise, the array isn't written
+         * to the StatsEvent and ERROR_LIST_TOO_LONG is appended to the
+         * StatsEvent errors field.
+         *
+         * @param elements array of floats.
+         **/
+        @RequiresApi(Build.VERSION_CODES.TIRAMISU)
+        @NonNull
+        public Builder writeFloatArray(@NonNull final float[] elements) {
+            final byte numElements = (byte)elements.length;
+
+            if (writeArrayInfo(numElements, TYPE_FLOAT)) {
+                // Write encoding of each element.
+                for (int i = 0; i < numElements; i++) {
+                  mPos += mBuffer.putFloat(mPos, elements[i]);
+                }
+                mNumElements++;
+            }
+            return this;
+        }
+
+        /**
+         * Write a repeated string field to this StatsEvent.
+         *
+         * The list size must not exceed 127. Otherwise, the array isn't written
+         * to the StatsEvent and ERROR_LIST_TOO_LONG is appended to the
+         * StatsEvent errors field.
+         *
+         * @param elements array of strings.
+         **/
+        @RequiresApi(Build.VERSION_CODES.TIRAMISU)
+        @NonNull
+        public Builder writeStringArray(@NonNull final String[] elements) {
+            final byte numElements = (byte)elements.length;
+
+            if (writeArrayInfo(numElements, TYPE_STRING)) {
+                // Write encoding of each element.
+                for (int i = 0; i < numElements; i++) {
+                    final byte[] elementBytes = stringToBytes(elements[i]);
+                    mPos += mBuffer.putInt(mPos, elementBytes.length);
+                    mPos += mBuffer.putByteArray(mPos, elementBytes);
+                }
+                mNumElements++;
+            }
+            return this;
+        }
+
+        /**
+         * Write a boolean annotation for the last field written.
+         **/
+        @NonNull
+        public Builder addBooleanAnnotation(
+                final byte annotationId, final boolean value) {
+            // Ensure there's a field written to annotate.
+            if (mNumElements < 2) {
+                mErrorMask |= ERROR_ANNOTATION_DOES_NOT_FOLLOW_FIELD;
+            } else if (mCurrentAnnotationCount >= MAX_ANNOTATION_COUNT) {
+                mErrorMask |= ERROR_TOO_MANY_ANNOTATIONS;
+            } else {
+                mPos += mBuffer.putByte(mPos, annotationId);
+                mPos += mBuffer.putByte(mPos, TYPE_BOOLEAN);
+                mPos += mBuffer.putBoolean(mPos, value);
+                mCurrentAnnotationCount++;
+                writeAnnotationCount();
+            }
+
+            return this;
+        }
+
+        /**
+         * Write an integer annotation for the last field written.
+         **/
+        @NonNull
+        public Builder addIntAnnotation(final byte annotationId, final int value) {
+            if (mNumElements < 2) {
+                mErrorMask |= ERROR_ANNOTATION_DOES_NOT_FOLLOW_FIELD;
+            } else if (mCurrentAnnotationCount >= MAX_ANNOTATION_COUNT) {
+                mErrorMask |= ERROR_TOO_MANY_ANNOTATIONS;
+            } else {
+                mPos += mBuffer.putByte(mPos, annotationId);
+                mPos += mBuffer.putByte(mPos, TYPE_INT);
+                mPos += mBuffer.putInt(mPos, value);
+                mCurrentAnnotationCount++;
+                writeAnnotationCount();
+            }
+
+            return this;
+        }
+
+        /**
+         * Indicates to reuse Buffer's byte array as the underlying payload in StatsEvent.
+         * This should be called for pushed events to reduce memory allocations and garbage
+         * collections.
+         **/
+        @NonNull
+        public Builder usePooledBuffer() {
+            mUsePooledBuffer = true;
+            mBuffer.setMaxSize(MAX_PUSH_PAYLOAD_SIZE, mPos);
+            return this;
+        }
+
+        /**
+         * Builds a StatsEvent object with values entered in this Builder.
+         **/
+        @NonNull
+        public StatsEvent build() {
+            if (0L == mTimestampNs) {
+                mErrorMask |= ERROR_NO_TIMESTAMP;
+            }
+            if (0 == mAtomId) {
+                mErrorMask |= ERROR_NO_ATOM_ID;
+            }
+            if (mBuffer.hasOverflowed()) {
+                mErrorMask |= ERROR_OVERFLOW;
+            }
+            if (mNumElements > MAX_NUM_ELEMENTS) {
+                mErrorMask |= ERROR_TOO_MANY_FIELDS;
+            }
+
+            if (0 == mErrorMask) {
+                mBuffer.putByte(POS_NUM_ELEMENTS, (byte) mNumElements);
+            } else {
+                // Write atom id and error mask. Overwrite any annotations for atom Id.
+                mPos = POS_ATOM_ID;
+                mPos += mBuffer.putByte(mPos, TYPE_INT);
+                mPos += mBuffer.putInt(mPos, mAtomId);
+                mPos += mBuffer.putByte(mPos, TYPE_ERRORS);
+                mPos += mBuffer.putInt(mPos, mErrorMask);
+                mBuffer.putByte(POS_NUM_ELEMENTS, (byte) 3);
+            }
+
+            final int size = mPos;
+
+            if (mUsePooledBuffer) {
+                return new StatsEvent(mAtomId, mBuffer, mBuffer.getBytes(), size);
+            } else {
+                // Create a copy of the buffer with the required number of bytes.
+                final byte[] payload = new byte[size];
+                System.arraycopy(mBuffer.getBytes(), 0, payload, 0, size);
+
+                // Return Buffer instance to the pool.
+                mBuffer.release();
+
+                return new StatsEvent(mAtomId, null, payload, size);
+            }
+        }
+
+        private void writeTypeId(final byte typeId) {
+            mPosLastField = mPos;
+            mLastType = typeId;
+            mCurrentAnnotationCount = 0;
+            final byte encodedId = (byte) (typeId & 0x0F);
+            mPos += mBuffer.putByte(mPos, encodedId);
+        }
+
+        private void writeAnnotationCount() {
+            // Use first 4 bits for annotation count and last 4 bits for typeId.
+            final byte encodedId = (byte) ((mCurrentAnnotationCount << 4) | (mLastType & 0x0F));
+            mBuffer.putByte(mPosLastField, encodedId);
+        }
+
+        @NonNull
+        private static byte[] stringToBytes(@Nullable final String value) {
+            return (null == value ? "" : value).getBytes(UTF_8);
+        }
+
+        private boolean writeArrayInfo(final byte numElements,
+                                       final byte elementTypeId) {
+            if (numElements > MAX_NUM_ELEMENTS) {
+                mErrorMask |= ERROR_LIST_TOO_LONG;
+                return false;
+            }
+            // Write list typeId byte, 1-byte representation of number of
+            // elements, and element typeId byte.
+            writeTypeId(TYPE_LIST);
+            mPos += mBuffer.putByte(mPos, numElements);
+            // Write element typeId byte without setting mPosLastField and mLastType (i.e. don't use
+            // #writeTypeId)
+            final byte encodedId = (byte) (elementTypeId & 0x0F);
+            mPos += mBuffer.putByte(mPos, encodedId);
+            return true;
+        }
+    }
+
+    private static final class Buffer {
+        private static Object sLock = new Object();
+
+        @GuardedBy("sLock")
+        private static Buffer sPool;
+
+        private byte[] mBytes;
+        private boolean mOverflow = false;
+        private int mMaxSize = MAX_PULL_PAYLOAD_SIZE;
+
+        @NonNull
+        private static Buffer obtain() {
+            final Buffer buffer;
+            synchronized (sLock) {
+                buffer = null == sPool ? new Buffer() : sPool;
+                sPool = null;
+            }
+            buffer.reset();
+            return buffer;
+        }
+
+        private Buffer() {
+            final ByteBuffer tempBuffer = ByteBuffer.allocateDirect(MAX_PUSH_PAYLOAD_SIZE);
+            mBytes = tempBuffer.hasArray() ? tempBuffer.array() : new byte [MAX_PUSH_PAYLOAD_SIZE];
+        }
+
+        @NonNull
+        private byte[] getBytes() {
+            return mBytes;
+        }
+
+        private void release() {
+            // Recycle this Buffer if its size is MAX_PUSH_PAYLOAD_SIZE or under.
+            if (mMaxSize <= MAX_PUSH_PAYLOAD_SIZE) {
+                synchronized (sLock) {
+                    if (null == sPool) {
+                        sPool = this;
+                    }
+                }
+            }
+        }
+
+        private void reset() {
+            mOverflow = false;
+            mMaxSize = MAX_PULL_PAYLOAD_SIZE;
+        }
+
+        private void setMaxSize(final int maxSize, final int numBytesWritten) {
+            mMaxSize = maxSize;
+            if (numBytesWritten > maxSize) {
+                mOverflow = true;
+            }
+        }
+
+        private boolean hasOverflowed() {
+            return mOverflow;
+        }
+
+        /**
+         * Checks for available space in the byte array.
+         *
+         * @param index starting position in the buffer to start the check.
+         * @param numBytes number of bytes to check from index.
+         * @return true if space is available, false otherwise.
+         **/
+        private boolean hasEnoughSpace(final int index, final int numBytes) {
+            final int totalBytesNeeded = index + numBytes;
+
+            if (totalBytesNeeded > mMaxSize) {
+                mOverflow = true;
+                return false;
+            }
+
+            // Expand buffer if needed.
+            if (mBytes.length < mMaxSize && totalBytesNeeded > mBytes.length) {
+                int newSize = mBytes.length;
+                do {
+                    newSize *= 2;
+                } while (newSize <= totalBytesNeeded);
+
+                if (newSize > mMaxSize) {
+                    newSize = mMaxSize;
+                }
+
+                mBytes = Arrays.copyOf(mBytes, newSize);
+            }
+
+            return true;
+        }
+
+        /**
+         * Writes a byte into the buffer.
+         *
+         * @param index position in the buffer where the byte is written.
+         * @param value the byte to write.
+         * @return number of bytes written to buffer from this write operation.
+         **/
+        private int putByte(final int index, final byte value) {
+            if (hasEnoughSpace(index, Byte.BYTES)) {
+                mBytes[index] = (byte) (value);
+                return Byte.BYTES;
+            }
+            return 0;
+        }
+
+        /**
+         * Writes a boolean into the buffer.
+         *
+         * @param index position in the buffer where the boolean is written.
+         * @param value the boolean to write.
+         * @return number of bytes written to buffer from this write operation.
+         **/
+        private int putBoolean(final int index, final boolean value) {
+            return putByte(index, (byte) (value ? 1 : 0));
+        }
+
+        /**
+         * Writes an integer into the buffer.
+         *
+         * @param index position in the buffer where the integer is written.
+         * @param value the integer to write.
+         * @return number of bytes written to buffer from this write operation.
+         **/
+        private int putInt(final int index, final int value) {
+            if (hasEnoughSpace(index, Integer.BYTES)) {
+                // Use little endian byte order.
+                mBytes[index] = (byte) (value);
+                mBytes[index + 1] = (byte) (value >> 8);
+                mBytes[index + 2] = (byte) (value >> 16);
+                mBytes[index + 3] = (byte) (value >> 24);
+                return Integer.BYTES;
+            }
+            return 0;
+        }
+
+        /**
+         * Writes a long into the buffer.
+         *
+         * @param index position in the buffer where the long is written.
+         * @param value the long to write.
+         * @return number of bytes written to buffer from this write operation.
+         **/
+        private int putLong(final int index, final long value) {
+            if (hasEnoughSpace(index, Long.BYTES)) {
+                // Use little endian byte order.
+                mBytes[index] = (byte) (value);
+                mBytes[index + 1] = (byte) (value >> 8);
+                mBytes[index + 2] = (byte) (value >> 16);
+                mBytes[index + 3] = (byte) (value >> 24);
+                mBytes[index + 4] = (byte) (value >> 32);
+                mBytes[index + 5] = (byte) (value >> 40);
+                mBytes[index + 6] = (byte) (value >> 48);
+                mBytes[index + 7] = (byte) (value >> 56);
+                return Long.BYTES;
+            }
+            return 0;
+        }
+
+        /**
+         * Writes a float into the buffer.
+         *
+         * @param index position in the buffer where the float is written.
+         * @param value the float to write.
+         * @return number of bytes written to buffer from this write operation.
+         **/
+        private int putFloat(final int index, final float value) {
+            return putInt(index, Float.floatToIntBits(value));
+        }
+
+        /**
+         * Copies a byte array into the buffer.
+         *
+         * @param index position in the buffer where the byte array is copied.
+         * @param value the byte array to copy.
+         * @return number of bytes written to buffer from this write operation.
+         **/
+        private int putByteArray(final int index, @NonNull final byte[] value) {
+            final int numBytes = value.length;
+            if (hasEnoughSpace(index, numBytes)) {
+                System.arraycopy(value, 0, mBytes, index, numBytes);
+                return numBytes;
+            }
+            return 0;
+        }
+    }
+}
diff --git a/ravenwood/runtime-helper-src/framework/android/util/StatsLog.java b/ravenwood/runtime-helper-src/framework/android/util/StatsLog.java
new file mode 100644
index 000000000000..c1c20cfac9dd
--- /dev/null
+++ b/ravenwood/runtime-helper-src/framework/android/util/StatsLog.java
@@ -0,0 +1,478 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.util;
+
+/*
+ * [Ravenwood] This is copied from StatsD, with the following changes:
+ * - The static {} is commented out.
+ * - All references to IStatsD and StatsdStatsLog are commented out.
+ * - The native method is no-oped.
+ */
+
+import static android.Manifest.permission.DUMP;
+import static android.Manifest.permission.PACKAGE_USAGE_STATS;
+
+import android.annotation.IntDef;
+import android.annotation.NonNull;
+import android.annotation.RequiresPermission;
+import android.annotation.SuppressLint;
+import android.annotation.SystemApi;
+import android.os.Build;
+//import android.os.IStatsd;
+import android.os.Process;
+import android.util.proto.ProtoOutputStream;
+
+import androidx.annotation.RequiresApi;
+
+//import com.android.internal.statsd.StatsdStatsLog;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+/**
+ * StatsLog provides an API for developers to send events to statsd. The events can be used to
+ * define custom metrics in side statsd.
+ */
+public final class StatsLog {
+
+//    // Load JNI library
+//    static {
+//        System.loadLibrary("stats_jni");
+//    }
+    private static final String TAG = "StatsLog";
+    private static final boolean DEBUG = false;
+    private static final int EXPERIMENT_IDS_FIELD_ID = 1;
+
+    /**
+     * Annotation ID constant for logging UID field.
+     *
+     * The ID is a byte since StatsEvent.addBooleanAnnotation() and StatsEvent.addIntAnnotation()
+     * accept byte as the type for annotation ids to save space.
+     *
+     * @hide
+     */
+    @SuppressLint("NoByteOrShort")
+    @SystemApi
+    public static final byte ANNOTATION_ID_IS_UID = 1;
+
+    /**
+     * Annotation ID constant to indicate logged atom event's timestamp should be truncated.
+     *
+     * The ID is a byte since StatsEvent.addBooleanAnnotation() and StatsEvent.addIntAnnotation()
+     * accept byte as the type for annotation ids to save space.
+     *
+     * @hide
+     */
+    @SuppressLint("NoByteOrShort")
+    @SystemApi
+    public static final byte ANNOTATION_ID_TRUNCATE_TIMESTAMP = 2;
+
+    /**
+     * Annotation ID constant for a state atom's primary field.
+     *
+     * The ID is a byte since StatsEvent.addBooleanAnnotation() and StatsEvent.addIntAnnotation()
+     * accept byte as the type for annotation ids to save space.
+     *
+     * @hide
+     */
+    @SuppressLint("NoByteOrShort")
+    @SystemApi
+    public static final byte ANNOTATION_ID_PRIMARY_FIELD = 3;
+
+    /**
+     * Annotation ID constant for state atom's state field.
+     *
+     * The ID is a byte since StatsEvent.addBooleanAnnotation() and StatsEvent.addIntAnnotation()
+     * accept byte as the type for annotation ids to save space.
+     *
+     * @hide
+     */
+    @SuppressLint("NoByteOrShort")
+    @SystemApi
+    public static final byte ANNOTATION_ID_EXCLUSIVE_STATE = 4;
+
+    /**
+     * Annotation ID constant to indicate the first UID in the attribution chain
+     * is a primary field.
+     * Should only be used for attribution chain fields.
+     *
+     * The ID is a byte since StatsEvent.addBooleanAnnotation() and StatsEvent.addIntAnnotation()
+     * accept byte as the type for annotation ids to save space.
+     *
+     * @hide
+     */
+    @SuppressLint("NoByteOrShort")
+    @SystemApi
+    public static final byte ANNOTATION_ID_PRIMARY_FIELD_FIRST_UID = 5;
+
+    /**
+     * Annotation ID constant to indicate which state is default for the state atom.
+     *
+     * The ID is a byte since StatsEvent.addBooleanAnnotation() and StatsEvent.addIntAnnotation()
+     * accept byte as the type for annotation ids to save space.
+     *
+     * @hide
+     */
+    @SuppressLint("NoByteOrShort")
+    @SystemApi
+    public static final byte ANNOTATION_ID_DEFAULT_STATE = 6;
+
+    /**
+     * Annotation ID constant to signal all states should be reset to the default state.
+     *
+     * The ID is a byte since StatsEvent.addBooleanAnnotation() and StatsEvent.addIntAnnotation()
+     * accept byte as the type for annotation ids to save space.
+     *
+     * @hide
+     */
+    @SuppressLint("NoByteOrShort")
+    @SystemApi
+    public static final byte ANNOTATION_ID_TRIGGER_STATE_RESET = 7;
+
+    /**
+     * Annotation ID constant to indicate state changes need to account for nesting.
+     * This should only be used with binary state atoms.
+     *
+     * The ID is a byte since StatsEvent.addBooleanAnnotation() and StatsEvent.addIntAnnotation()
+     * accept byte as the type for annotation ids to save space.
+     *
+     * @hide
+     */
+    @SuppressLint("NoByteOrShort")
+    @SystemApi
+    public static final byte ANNOTATION_ID_STATE_NESTED = 8;
+
+    /**
+     * Annotation ID constant to indicate the restriction category of an atom.
+     * This annotation must only be attached to the atom id. This is an int annotation.
+     *
+     * The ID is a byte since StatsEvent.addBooleanAnnotation() and StatsEvent.addIntAnnotation()
+     * accept byte as the type for annotation ids to save space.
+     *
+     * @hide
+     */
+    @SuppressLint("NoByteOrShort")
+    @SystemApi
+    @RequiresApi(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
+    public static final byte ANNOTATION_ID_RESTRICTION_CATEGORY = 9;
+
+    /**
+     * Annotation ID to indicate that a field of an atom contains peripheral device info.
+     * This is a bool annotation.
+     *
+     * The ID is a byte since StatsEvent.addBooleanAnnotation() and StatsEvent.addIntAnnotation()
+     * accept byte as the type for annotation ids to save space.
+     *
+     * @hide
+     */
+    @SuppressLint("NoByteOrShort")
+    @SystemApi
+    @RequiresApi(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
+    public static final byte ANNOTATION_ID_FIELD_RESTRICTION_PERIPHERAL_DEVICE_INFO = 10;
+
+    /**
+     * Annotation ID to indicate that a field of an atom contains app usage information.
+     * This is a bool annotation.
+     *
+     * The ID is a byte since StatsEvent.addBooleanAnnotation() and StatsEvent.addIntAnnotation()
+     * accept byte as the type for annotation ids to save space.
+     *
+     * @hide
+     */
+    @SuppressLint("NoByteOrShort")
+    @SystemApi
+    @RequiresApi(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
+    public static final byte ANNOTATION_ID_FIELD_RESTRICTION_APP_USAGE = 11;
+
+    /**
+     * Annotation ID to indicate that a field of an atom contains app activity information.
+     * This is a bool annotation.
+     *
+     * The ID is a byte since StatsEvent.addBooleanAnnotation() and StatsEvent.addIntAnnotation()
+     * accept byte as the type for annotation ids to save space.
+     *
+     * @hide
+     */
+    @SuppressLint("NoByteOrShort")
+    @SystemApi
+    @RequiresApi(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
+    public static final byte ANNOTATION_ID_FIELD_RESTRICTION_APP_ACTIVITY = 12;
+
+    /**
+     * Annotation ID to indicate that a field of an atom contains health connect information.
+     * This is a bool annotation.
+     *
+     * The ID is a byte since StatsEvent.addBooleanAnnotation() and StatsEvent.addIntAnnotation()
+     * accept byte as the type for annotation ids to save space.
+     *
+     * @hide
+     */
+    @SuppressLint("NoByteOrShort")
+    @SystemApi
+    @RequiresApi(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
+    public static final byte ANNOTATION_ID_FIELD_RESTRICTION_HEALTH_CONNECT = 13;
+
+    /**
+     * Annotation ID to indicate that a field of an atom contains accessibility information.
+     * This is a bool annotation.
+     *
+     * The ID is a byte since StatsEvent.addBooleanAnnotation() and StatsEvent.addIntAnnotation()
+     * accept byte as the type for annotation ids to save space.
+     *
+     * @hide
+     */
+    @SuppressLint("NoByteOrShort")
+    @SystemApi
+    @RequiresApi(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
+    public static final byte ANNOTATION_ID_FIELD_RESTRICTION_ACCESSIBILITY = 14;
+
+    /**
+     * Annotation ID to indicate that a field of an atom contains system search information.
+     * This is a bool annotation.
+     *
+     * The ID is a byte since StatsEvent.addBooleanAnnotation() and StatsEvent.addIntAnnotation()
+     * accept byte as the type for annotation ids to save space.
+     *
+     * @hide
+     */
+    @SuppressLint("NoByteOrShort")
+    @SystemApi
+    @RequiresApi(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
+    public static final byte ANNOTATION_ID_FIELD_RESTRICTION_SYSTEM_SEARCH = 15;
+
+    /**
+     * Annotation ID to indicate that a field of an atom contains user engagement information.
+     * This is a bool annotation.
+     *
+     * The ID is a byte since StatsEvent.addBooleanAnnotation() and StatsEvent.addIntAnnotation()
+     * accept byte as the type for annotation ids to save space.
+     *
+     * @hide
+     */
+    @SuppressLint("NoByteOrShort")
+    @SystemApi
+    @RequiresApi(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
+    public static final byte ANNOTATION_ID_FIELD_RESTRICTION_USER_ENGAGEMENT = 16;
+
+    /**
+     * Annotation ID to indicate that a field of an atom contains ambient sensing information.
+     * This is a bool annotation.
+     *
+     * The ID is a byte since StatsEvent.addBooleanAnnotation() and StatsEvent.addIntAnnotation()
+     * accept byte as the type for annotation ids to save space.
+     *
+     * @hide
+     */
+    @SuppressLint("NoByteOrShort")
+    @SystemApi
+    @RequiresApi(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
+    public static final byte ANNOTATION_ID_FIELD_RESTRICTION_AMBIENT_SENSING = 17;
+
+    /**
+     * Annotation ID to indicate that a field of an atom contains demographic classification
+     * information. This is a bool annotation.
+     *
+     * The ID is a byte since StatsEvent.addBooleanAnnotation() and StatsEvent.addIntAnnotation()
+     * accept byte as the type for annotation ids to save space.
+     *
+     * @hide
+     */
+    @SuppressLint("NoByteOrShort")
+    @SystemApi
+    @RequiresApi(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
+    public static final byte ANNOTATION_ID_FIELD_RESTRICTION_DEMOGRAPHIC_CLASSIFICATION = 18;
+
+
+    /** @hide */
+    @IntDef(prefix = { "RESTRICTION_CATEGORY_" }, value = {
+            RESTRICTION_CATEGORY_DIAGNOSTIC,
+            RESTRICTION_CATEGORY_SYSTEM_INTELLIGENCE,
+            RESTRICTION_CATEGORY_AUTHENTICATION,
+            RESTRICTION_CATEGORY_FRAUD_AND_ABUSE})
+    @Retention(RetentionPolicy.SOURCE)
+    public @interface RestrictionCategory {}
+
+    /**
+     * Restriction category for atoms about diagnostics.
+     *
+     * @hide
+     */
+    @SystemApi
+    @RequiresApi(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
+    public static final int RESTRICTION_CATEGORY_DIAGNOSTIC = 1;
+
+    /**
+     * Restriction category for atoms about system intelligence.
+     *
+     * @hide
+     */
+    @SystemApi
+    @RequiresApi(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
+    public static final int RESTRICTION_CATEGORY_SYSTEM_INTELLIGENCE = 2;
+
+    /**
+     * Restriction category for atoms about authentication.
+     *
+     * @hide
+     */
+    @SystemApi
+    @RequiresApi(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
+    public static final int RESTRICTION_CATEGORY_AUTHENTICATION = 3;
+
+    /**
+     * Restriction category for atoms about fraud and abuse.
+     *
+     * @hide
+     */
+    @SystemApi
+    @RequiresApi(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
+    public static final int RESTRICTION_CATEGORY_FRAUD_AND_ABUSE = 4;
+
+    private StatsLog() {
+    }
+
+    /**
+     * Logs a start event.
+     *
+     * @param label developer-chosen label.
+     * @return True if the log request was sent to statsd.
+     */
+    public static boolean logStart(int label) {
+        int callingUid = Process.myUid();
+//        StatsdStatsLog.write(
+//                StatsdStatsLog.APP_BREADCRUMB_REPORTED,
+//                callingUid,
+//                label,
+//                StatsdStatsLog.APP_BREADCRUMB_REPORTED__STATE__START);
+        return true;
+    }
+
+    /**
+     * Logs a stop event.
+     *
+     * @param label developer-chosen label.
+     * @return True if the log request was sent to statsd.
+     */
+    public static boolean logStop(int label) {
+        int callingUid = Process.myUid();
+//        StatsdStatsLog.write(
+//                StatsdStatsLog.APP_BREADCRUMB_REPORTED,
+//                callingUid,
+//                label,
+//                StatsdStatsLog.APP_BREADCRUMB_REPORTED__STATE__STOP);
+        return true;
+    }
+
+    /**
+     * Logs an event that does not represent a start or stop boundary.
+     *
+     * @param label developer-chosen label.
+     * @return True if the log request was sent to statsd.
+     */
+    public static boolean logEvent(int label) {
+        int callingUid = Process.myUid();
+//        StatsdStatsLog.write(
+//                StatsdStatsLog.APP_BREADCRUMB_REPORTED,
+//                callingUid,
+//                label,
+//                StatsdStatsLog.APP_BREADCRUMB_REPORTED__STATE__UNSPECIFIED);
+        return true;
+    }
+
+    /**
+     * Logs an event for binary push for module updates.
+     *
+     * @param trainName        name of install train.
+     * @param trainVersionCode version code of the train.
+     * @param options          optional flags about this install.
+     *                         The last 3 bits indicate options:
+     *                             0x01: FLAG_REQUIRE_STAGING
+     *                             0x02: FLAG_ROLLBACK_ENABLED
+     *                             0x04: FLAG_REQUIRE_LOW_LATENCY_MONITOR
+     * @param state            current install state. Defined as State enums in
+     *                         BinaryPushStateChanged atom in
+     *                         frameworks/proto_logging/stats/atoms.proto
+     * @param experimentIds    experiment ids.
+     * @return True if the log request was sent to statsd.
+     */
+    @RequiresPermission(allOf = {DUMP, PACKAGE_USAGE_STATS})
+    public static boolean logBinaryPushStateChanged(@NonNull String trainName,
+            long trainVersionCode, int options, int state,
+            @NonNull long[] experimentIds) {
+        ProtoOutputStream proto = new ProtoOutputStream();
+        for (long id : experimentIds) {
+            proto.write(
+                    ProtoOutputStream.FIELD_TYPE_INT64
+                    | ProtoOutputStream.FIELD_COUNT_REPEATED
+                    | EXPERIMENT_IDS_FIELD_ID,
+                    id);
+        }
+//        StatsdStatsLog.write(StatsdStatsLog.BINARY_PUSH_STATE_CHANGED,
+//                trainName,
+//                trainVersionCode,
+//                (options & IStatsd.FLAG_REQUIRE_STAGING) > 0,
+//                (options & IStatsd.FLAG_ROLLBACK_ENABLED) > 0,
+//                (options & IStatsd.FLAG_REQUIRE_LOW_LATENCY_MONITOR) > 0,
+//                state,
+//                proto.getBytes(),
+//                0,
+//                0,
+//                false);
+        return true;
+    }
+
+    /**
+     * Write an event to stats log using the raw format.
+     *
+     * @param buffer    The encoded buffer of data to write.
+     * @param size      The number of bytes from the buffer to write.
+     * @hide
+     * @deprecated Use {@link write(final StatsEvent statsEvent)} instead.
+     *
+     */
+    @Deprecated
+    @SystemApi
+    public static void writeRaw(@NonNull byte[] buffer, int size) {
+        writeImpl(buffer, size, 0);
+    }
+
+    /**
+     * Write an event to stats log using the raw format.
+     *
+     * @param buffer    The encoded buffer of data to write.
+     * @param size      The number of bytes from the buffer to write.
+     * @param atomId    The id of the atom to which the event belongs.
+     */
+//    private static native void writeImpl(@NonNull byte[] buffer, int size, int atomId);
+    private static void writeImpl(@NonNull byte[] buffer, int size, int atomId) {
+        // no-op for now
+    }
+
+    /**
+     * Write an event to stats log using the raw format encapsulated in StatsEvent.
+     * After writing to stats log, release() is called on the StatsEvent object.
+     * No further action should be taken on the StatsEvent object following this call.
+     *
+     * @param statsEvent    The StatsEvent object containing the encoded buffer of data to write.
+     * @hide
+     */
+    @SystemApi
+    public static void write(@NonNull final StatsEvent statsEvent) {
+        writeImpl(statsEvent.getBytes(), statsEvent.getNumBytes(), statsEvent.getAtomId());
+        statsEvent.release();
+    }
+}
diff --git a/ravenwood/runtime-helper-src/libcore-fake/android/compat/Compatibility.java b/ravenwood/runtime-helper-src/libcore-fake/android/compat/Compatibility.java
new file mode 100644
index 000000000000..c7376842d8f3
--- /dev/null
+++ b/ravenwood/runtime-helper-src/libcore-fake/android/compat/Compatibility.java
@@ -0,0 +1,359 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.compat;
+
+// [Ravenwood] Copied from libcore, with "RAVENWOOD-CHANGE"
+
+import static android.annotation.SystemApi.Client.MODULE_LIBRARIES;
+
+import android.annotation.SystemApi;
+import android.compat.annotation.ChangeId;
+
+import libcore.api.IntraCoreApi;
+import libcore.util.NonNull;
+
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Objects;
+import java.util.Set;
+
+/**
+ * Internal APIs for logging and gating compatibility changes.
+ *
+ * @see ChangeId
+ *
+ * @hide
+ */
+@SystemApi(client = MODULE_LIBRARIES)
+@IntraCoreApi
+public final class Compatibility {
+
+    private Compatibility() {}
+
+    /**
+     * Reports that a compatibility change is affecting the current process now.
+     *
+     * <p>Calls to this method from a non-app process are ignored. This allows code implementing
+     * APIs that are used by apps and by other code (e.g. the system server) to report changes
+     * regardless of the process it's running in. When called in a non-app process, this method is
+     * a no-op.
+     *
+     * <p>Note: for changes that are gated using {@link #isChangeEnabled(long)}, you do not need to
+     * call this API directly. The change will be reported for you in the case that
+     * {@link #isChangeEnabled(long)} returns {@code true}.
+     *
+     * @param changeId The ID of the compatibility change taking effect.
+     *
+     * @hide
+     */
+    @SystemApi(client = MODULE_LIBRARIES)
+    @IntraCoreApi
+    public static void reportUnconditionalChange(@ChangeId long changeId) {
+        sCallbacks.onChangeReported(changeId);
+    }
+
+    /**
+     * Query if a given compatibility change is enabled for the current process. This method should
+     * only be called by code running inside a process of the affected app.
+     *
+     * <p>If this method returns {@code true}, the calling code should implement the compatibility
+     * change, resulting in differing behaviour compared to earlier releases. If this method returns
+     * {@code false}, the calling code should behave as it did in earlier releases.
+     *
+     * <p>When this method returns {@code true}, it will also report the change as
+     * {@link #reportUnconditionalChange(long)} would, so there is no need to call that method
+     * directly.
+     *
+     * @param changeId The ID of the compatibility change in question.
+     * @return {@code true} if the change is enabled for the current app.
+     *
+     * @hide
+     */
+    @SystemApi(client = MODULE_LIBRARIES)
+    @IntraCoreApi
+    public static boolean isChangeEnabled(@ChangeId long changeId) {
+        return sCallbacks.isChangeEnabled(changeId);
+    }
+
+    private static final BehaviorChangeDelegate DEFAULT_CALLBACKS = new BehaviorChangeDelegate(){};
+
+    private volatile static BehaviorChangeDelegate sCallbacks = DEFAULT_CALLBACKS;
+
+    /**
+     * Sets the behavior change delegate.
+     *
+     * All changes reported via the {@link Compatibility} class will be forwarded to this class.
+     *
+     * @hide
+     */
+    @SystemApi(client = MODULE_LIBRARIES)
+    public static void setBehaviorChangeDelegate(BehaviorChangeDelegate callbacks) {
+        sCallbacks = Objects.requireNonNull(callbacks);
+    }
+
+    /**
+     * Removes a behavior change delegate previously set via {@link #setBehaviorChangeDelegate}.
+     *
+     * @hide
+     */
+    @SystemApi(client = MODULE_LIBRARIES)
+    public static void clearBehaviorChangeDelegate() {
+        sCallbacks = DEFAULT_CALLBACKS;
+    }
+
+    /**
+     * Return the behavior change delegate
+     *
+     * @hide
+     */
+    // VisibleForTesting
+    @NonNull
+    public static BehaviorChangeDelegate getBehaviorChangeDelegate() {
+        return sCallbacks;
+    }
+
+    /**
+     * For use by tests only. Causes values from {@code overrides} to be returned instead of the
+     * real value.
+     *
+     * @hide
+     */
+    @SystemApi(client = MODULE_LIBRARIES)
+    public static void setOverrides(ChangeConfig overrides) {
+        // Setting overrides twice in a row does not need to be supported because
+        // this method is only for enabling/disabling changes for the duration of
+        // a single test.
+        // In production, the app is restarted when changes get enabled or disabled,
+        // and the ChangeConfig is then set exactly once on that app process.
+        if (sCallbacks instanceof OverrideCallbacks) {
+            throw new IllegalStateException("setOverrides has already been called!");
+        }
+        sCallbacks = new OverrideCallbacks(sCallbacks, overrides);
+    }
+
+    /**
+     * For use by tests only. Removes overrides set by {@link #setOverrides}.
+     *
+     * @hide
+     */
+    @SystemApi(client = MODULE_LIBRARIES)
+    public static void clearOverrides() {
+        if (!(sCallbacks instanceof OverrideCallbacks)) {
+            throw new IllegalStateException("No overrides set");
+        }
+        sCallbacks = ((OverrideCallbacks) sCallbacks).delegate;
+    }
+
+    /**
+     * Base class for compatibility API implementations. The default implementation logs a warning
+     * to logcat.
+     *
+     * This is provided as a class rather than an interface to allow new methods to be added without
+     * breaking @SystemApi binary compatibility.
+     *
+     * @hide
+     */
+    @SystemApi(client = MODULE_LIBRARIES)
+    public interface BehaviorChangeDelegate {
+        /**
+         * Called when a change is reported via {@link Compatibility#reportUnconditionalChange}
+         *
+         * @hide
+         */
+        @SystemApi(client = MODULE_LIBRARIES)
+        default void onChangeReported(long changeId) {
+            // Do not use String.format here (b/160912695)
+
+            // RAVENWOOD-CHANGE
+            System.out.println("No Compatibility callbacks set! Reporting change " + changeId);
+        }
+
+        /**
+         * Called when a change is queried via {@link Compatibility#isChangeEnabled}
+         *
+         * @hide
+         */
+        @SystemApi(client = MODULE_LIBRARIES)
+        default boolean isChangeEnabled(long changeId) {
+            // Do not use String.format here (b/160912695)
+            // TODO(b/289900411): Rate limit this log if it's necessary in the release build.
+            // System.logW("No Compatibility callbacks set! Querying change " + changeId);
+            return true;
+        }
+    }
+
+    /**
+     * @hide
+     */
+    @SystemApi(client = MODULE_LIBRARIES)
+    @IntraCoreApi
+    public static final class ChangeConfig {
+        private final Set<Long> enabled;
+        private final Set<Long> disabled;
+
+        /**
+         * @hide
+         */
+        @SystemApi(client = MODULE_LIBRARIES)
+        @IntraCoreApi
+        public ChangeConfig(@NonNull Set<@NonNull Long> enabled, @NonNull Set<@NonNull Long> disabled) {
+            this.enabled = Objects.requireNonNull(enabled);
+            this.disabled = Objects.requireNonNull(disabled);
+            if (enabled.contains(null)) {
+                throw new NullPointerException();
+            }
+            if (disabled.contains(null)) {
+                throw new NullPointerException();
+            }
+            Set<Long> intersection = new HashSet<>(enabled);
+            intersection.retainAll(disabled);
+            if (!intersection.isEmpty()) {
+                throw new IllegalArgumentException("Cannot have changes " + intersection
+                        + " enabled and disabled!");
+            }
+        }
+
+        /**
+         * @hide
+         */
+        @SystemApi(client = MODULE_LIBRARIES)
+        @IntraCoreApi
+        public boolean isEmpty() {
+            return enabled.isEmpty() && disabled.isEmpty();
+        }
+
+        private static long[] toLongArray(Set<Long> values) {
+            long[] result = new long[values.size()];
+            int idx = 0;
+            for (Long value: values) {
+                result[idx++] = value;
+            }
+            return result;
+        }
+
+        /**
+         * @hide
+         */
+        @SystemApi(client = MODULE_LIBRARIES)
+        @IntraCoreApi
+        public @NonNull long[] getEnabledChangesArray() {
+            return toLongArray(enabled);
+        }
+
+
+        /**
+         * @hide
+         */
+        @SystemApi(client = MODULE_LIBRARIES)
+        @IntraCoreApi
+        public @NonNull long[] getDisabledChangesArray() {
+            return toLongArray(disabled);
+        }
+
+
+        /**
+         * @hide
+         */
+        @SystemApi(client = MODULE_LIBRARIES)
+        @IntraCoreApi
+        public @NonNull Set<@NonNull Long> getEnabledSet() {
+            return Collections.unmodifiableSet(enabled);
+        }
+
+
+        /**
+         * @hide
+         */
+        @SystemApi(client = MODULE_LIBRARIES)
+        @IntraCoreApi
+        public @NonNull Set<@NonNull Long> getDisabledSet() {
+            return Collections.unmodifiableSet(disabled);
+        }
+
+
+        /**
+         * @hide
+         */
+        @SystemApi(client = MODULE_LIBRARIES)
+        @IntraCoreApi
+        public boolean isForceEnabled(long changeId) {
+            return enabled.contains(changeId);
+        }
+
+
+        /**
+         * @hide
+         */
+        @SystemApi(client = MODULE_LIBRARIES)
+        @IntraCoreApi
+        public boolean isForceDisabled(long changeId) {
+            return disabled.contains(changeId);
+        }
+
+
+        /**
+         * @hide
+         */
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (!(o instanceof ChangeConfig)) {
+                return false;
+            }
+            ChangeConfig that = (ChangeConfig) o;
+            return enabled.equals(that.enabled) &&
+                    disabled.equals(that.disabled);
+        }
+
+        /**
+         * @hide
+         */
+        @Override
+        public int hashCode() {
+            return Objects.hash(enabled, disabled);
+        }
+
+
+        /**
+         * @hide
+         */
+        @Override
+        public String toString() {
+            return "ChangeConfig{enabled=" + enabled + ", disabled=" + disabled + '}';
+        }
+    }
+
+    private static class OverrideCallbacks implements BehaviorChangeDelegate {
+        private final BehaviorChangeDelegate delegate;
+        private final ChangeConfig changeConfig;
+
+        private OverrideCallbacks(BehaviorChangeDelegate delegate, ChangeConfig changeConfig) {
+            this.delegate = Objects.requireNonNull(delegate);
+            this.changeConfig = Objects.requireNonNull(changeConfig);
+        }
+        @Override
+        public boolean isChangeEnabled(long changeId) {
+           if (changeConfig.isForceEnabled(changeId)) {
+               return true;
+           }
+           if (changeConfig.isForceDisabled(changeId)) {
+               return false;
+           }
+           return delegate.isChangeEnabled(changeId);
+        }
+    }
+}
diff --git a/ravenwood/runtime-helper-src/libcore-fake/libcore/api/CorePlatformApi.java b/ravenwood/runtime-helper-src/libcore-fake/libcore/api/CorePlatformApi.java
new file mode 100644
index 000000000000..00730efc64b3
--- /dev/null
+++ b/ravenwood/runtime-helper-src/libcore-fake/libcore/api/CorePlatformApi.java
@@ -0,0 +1,69 @@
+
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package libcore.api;
+
+import static java.lang.annotation.ElementType.ANNOTATION_TYPE;
+import static java.lang.annotation.ElementType.CONSTRUCTOR;
+import static java.lang.annotation.ElementType.FIELD;
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.ElementType.TYPE;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Indicates an API is part of a contract provided by the "core" set of
+ * libraries to select parts of the Android software stack.
+ *
+ * <p>This annotation should only appear on either (a) classes that are hidden by <pre>@hide</pre>
+ * javadoc tags or equivalent annotations, or (b) members of such classes. It is for use with
+ * metalava's {@code --show-single-annotation} option and so must be applied at the class level and
+ * applied again each member that is to be made part of the API. Members that are not part of the
+ * API do not have to be explicitly hidden.
+ *
+ * @hide
+ */
+@IntraCoreApi
+@Target({TYPE, FIELD, METHOD, CONSTRUCTOR, ANNOTATION_TYPE})
+@Retention(RetentionPolicy.SOURCE)
+public @interface CorePlatformApi {
+
+    /** Enumeration of the possible statuses of the API in the core/platform API surface. */
+    @IntraCoreApi
+    enum Status {
+
+        /**
+         * This API is considered stable, and so present in both the stable and legacy version of
+         * the API surface.
+        */
+        @IntraCoreApi
+        STABLE,
+
+        /**
+         * This API is not (yet) considered stable, and so only present in the legacy version of
+         * the API surface.
+         */
+        @IntraCoreApi
+        LEGACY_ONLY
+    }
+
+    /** The status of the API in the core/platform API surface. */
+    @IntraCoreApi
+    Status status() default Status.LEGACY_ONLY;
+}
diff --git a/ravenwood/runtime-helper-src/libcore-fake/libcore/api/Hide.java b/ravenwood/runtime-helper-src/libcore-fake/libcore/api/Hide.java
new file mode 100644
index 000000000000..f87ff11df0ab
--- /dev/null
+++ b/ravenwood/runtime-helper-src/libcore-fake/libcore/api/Hide.java
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package libcore.api;
+
+import static java.lang.annotation.ElementType.ANNOTATION_TYPE;
+import static java.lang.annotation.ElementType.CONSTRUCTOR;
+import static java.lang.annotation.ElementType.FIELD;
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.ElementType.TYPE;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Indicates that an API is hidden by default, in a similar fashion to the
+ * <pre>@hide</pre> javadoc tag.
+ *
+ * <p>Note that, in order for this to work, metalava has to be invoked with
+ * the flag {@code --hide-annotation libcore.api.Hide}.
+ *
+ * <p>This annotation should be used in {@code .annotated.java} stub files which
+ * contain API inclusion information about {@code libcore/ojluni} classes, to
+ * avoid patching the source files with <pre>@hide</pre> javadoc tags. All
+ * build targets which consume these stub files should also apply the above
+ * metalava flag.
+ *
+ * @hide
+ */
+@Target({TYPE, FIELD, METHOD, CONSTRUCTOR, ANNOTATION_TYPE})
+@Retention(RetentionPolicy.SOURCE)
+public @interface Hide {
+}
diff --git a/ravenwood/runtime-helper-src/libcore-fake/libcore/api/IntraCoreApi.java b/ravenwood/runtime-helper-src/libcore-fake/libcore/api/IntraCoreApi.java
new file mode 100644
index 000000000000..87cfcff2474b
--- /dev/null
+++ b/ravenwood/runtime-helper-src/libcore-fake/libcore/api/IntraCoreApi.java
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package libcore.api;
+
+import static java.lang.annotation.ElementType.ANNOTATION_TYPE;
+import static java.lang.annotation.ElementType.CONSTRUCTOR;
+import static java.lang.annotation.ElementType.FIELD;
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.ElementType.TYPE;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Indicates an API is part of a contract within the "core" set of libraries, some of which may
+ * be mmodules.
+ *
+ * <p>This annotation should only appear on either (a) classes that are hidden by <pre>@hide</pre>
+ * javadoc tags or equivalent annotations, or (b) members of such classes. It is for use with
+ * metalava's {@code --show-single-annotation} option and so must be applied at the class level and
+ * applied again each member that is to be made part of the API. Members that are not part of the
+ * API do not have to be explicitly hidden.
+ *
+ * @hide
+ */
+@IntraCoreApi // @IntraCoreApi is itself part of the intra-core API
+@Target({TYPE, FIELD, METHOD, CONSTRUCTOR, ANNOTATION_TYPE})
+@Retention(RetentionPolicy.SOURCE)
+public @interface IntraCoreApi {
+}
diff --git a/ravenwood/runtime-helper-src/libcore-fake/libcore/util/NonNull.java b/ravenwood/runtime-helper-src/libcore-fake/libcore/util/NonNull.java
new file mode 100644
index 000000000000..db3cd8ed712f
--- /dev/null
+++ b/ravenwood/runtime-helper-src/libcore-fake/libcore/util/NonNull.java
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package libcore.util;
+
+import static java.lang.annotation.ElementType.FIELD;
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.ElementType.PARAMETER;
+import static java.lang.annotation.ElementType.TYPE_USE;
+import static java.lang.annotation.RetentionPolicy.SOURCE;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+/**
+ * Denotes that a type use can never be null.
+ * <p>
+ * This is a marker annotation and it has no specific attributes.
+ * @hide
+ */
+@Documented
+@Retention(SOURCE)
+@Target({FIELD, METHOD, PARAMETER, TYPE_USE})
+@libcore.api.IntraCoreApi
+public @interface NonNull {
+   /**
+    * Min Android API level (inclusive) to which this annotation is applied.
+    */
+   int from() default Integer.MIN_VALUE;
+
+   /**
+    * Max Android API level to which this annotation is applied.
+    */
+   int to() default Integer.MAX_VALUE;
+}
diff --git a/ravenwood/runtime-helper-src/libcore-fake/libcore/util/Nullable.java b/ravenwood/runtime-helper-src/libcore-fake/libcore/util/Nullable.java
new file mode 100644
index 000000000000..3371978b0568
--- /dev/null
+++ b/ravenwood/runtime-helper-src/libcore-fake/libcore/util/Nullable.java
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package libcore.util;
+
+import static java.lang.annotation.ElementType.FIELD;
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.ElementType.PARAMETER;
+import static java.lang.annotation.ElementType.TYPE_USE;
+import static java.lang.annotation.RetentionPolicy.SOURCE;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+/**
+ * Denotes that a type use can be a null.
+ * <p>
+ * This is a marker annotation and it has no specific attributes.
+ * @hide
+ */
+@Documented
+@Retention(SOURCE)
+@Target({FIELD, METHOD, PARAMETER, TYPE_USE})
+@libcore.api.IntraCoreApi
+public @interface Nullable {
+   /**
+    * Min Android API level (inclusive) to which this annotation is applied.
+    */
+   int from() default Integer.MIN_VALUE;
+
+   /**
+    * Max Android API level to which this annotation is applied.
+    */
+   int to() default Integer.MAX_VALUE;
+}
diff --git a/ravenwood/texts/ravenwood-framework-policies.txt b/ravenwood/texts/ravenwood-framework-policies.txt
index 3649f0e78f09..b64944ee39ed 100644
--- a/ravenwood/texts/ravenwood-framework-policies.txt
+++ b/ravenwood/texts/ravenwood-framework-policies.txt
@@ -5,6 +5,10 @@
 rename com/.*/nano/   devicenano/
 rename android/.*/nano/   devicenano/
 
+
+# StatsD autogenerated classes. Maybe add a heuristic?
+class com.android.internal.util.FrameworkStatsLog keepclass
+
 # Exported to Mainline modules; cannot use annotations
 class com.android.internal.util.FastXmlSerializer keepclass
 class com.android.internal.util.FileRotator keepclass