Revert "Connect FeatureFlags with FeatureFlagsService."

Revert submission 23727772-b279054964-flag-api-udc-qpr-dev

Reason for revert: b/290929382

Reverted changes: /q/submissionid:23727772-b279054964-flag-api-udc-qpr-dev

Change-Id: I5ebfe5ac5ac518f33c4bd3beaa4cd018b43242cf

12 files changed, 143 insertions, 592 deletions

diff --git a/core/java/android/flags/BooleanFlag.java b/core/java/android/flags/BooleanFlag.java
index ae9ccf8c52c3..5519961a917f 100644
--- a/core/java/android/flags/BooleanFlag.java
+++ b/core/java/android/flags/BooleanFlag.java
@@ -25,7 +25,9 @@ import android.annotation.NonNull;
  *
  * @hide
  */
-public class BooleanFlag extends BooleanFlagBase {
+public class BooleanFlag implements Flag<Boolean> {
+    private final String mNamespace;
+    private final String mName;
     private final boolean mDefault;
 
     /**
@@ -34,7 +36,8 @@ public class BooleanFlag extends BooleanFlagBase {
      * @param defaultValue The value of this flag if no other override is present.
      */
     BooleanFlag(String namespace, String name, boolean defaultValue) {
-        super(namespace, name);
+        mNamespace = namespace;
+        mName = name;
         mDefault = defaultValue;
     }
 
@@ -43,4 +46,22 @@ public class BooleanFlag extends BooleanFlagBase {
     public Boolean getDefault() {
         return mDefault;
     }
+
+    @Override
+    @NonNull
+    public String getNamespace() {
+        return mNamespace;
+    }
+
+    @Override
+    @NonNull
+    public String getName() {
+        return mName;
+    }
+
+    @Override
+    @NonNull
+    public String toString() {
+        return getNamespace() + "." + getName() + "[" + getDefault() + "]";
+    }
 }
diff --git a/core/java/android/flags/BooleanFlagBase.java b/core/java/android/flags/BooleanFlagBase.java
deleted file mode 100644
index f4141ecab01b..000000000000
--- a/core/java/android/flags/BooleanFlagBase.java
+++ /dev/null
@@ -1,54 +0,0 @@
-/*
- * Copyright (C) 2023 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.flags;
-
-import android.annotation.NonNull;
-
-abstract class BooleanFlagBase implements Flag<Boolean> {
-
-    private final String mNamespace;
-    private final String mName;
-
-    /**
-     * @param namespace A namespace for this flag. See {@link android.provider.DeviceConfig}.
-     * @param name A name for this flag.
-     */
-    BooleanFlagBase(String namespace, String name) {
-        mNamespace = namespace;
-        mName = name;
-    }
-
-    public abstract Boolean getDefault();
-
-    @Override
-    @NonNull
-    public String getNamespace() {
-        return mNamespace;
-    }
-
-    @Override
-    @NonNull
-    public String getName() {
-        return mName;
-    }
-
-    @Override
-    @NonNull
-    public String toString() {
-        return getNamespace() + "." + getName() + "[" + getDefault() + "]";
-    }
-}
diff --git a/core/java/android/flags/DynamicBooleanFlag.java b/core/java/android/flags/DynamicBooleanFlag.java
index 92009c60d91a..d76fd9ec9a3c 100644
--- a/core/java/android/flags/DynamicBooleanFlag.java
+++ b/core/java/android/flags/DynamicBooleanFlag.java
@@ -23,8 +23,10 @@ package android.flags;
  *
  * @hide
  */
-public class DynamicBooleanFlag extends BooleanFlagBase implements DynamicFlag<Boolean> {
+public class DynamicBooleanFlag implements DynamicFlag<Boolean> {
 
+    private final String mNamespace;
+    private final String mName;
     private final boolean mDefault;
 
     /**
@@ -33,12 +35,28 @@ public class DynamicBooleanFlag extends BooleanFlagBase implements DynamicFlag<B
      * @param defaultValue The value of this flag if no other override is present.
      */
     DynamicBooleanFlag(String namespace, String name, boolean defaultValue) {
-        super(namespace, name);
+        mNamespace = namespace;
+        mName = name;
         mDefault = defaultValue;
     }
 
     @Override
+    public String getNamespace() {
+        return mNamespace;
+    }
+
+    @Override
+    public String getName() {
+        return mName;
+    }
+
+    @Override
     public Boolean getDefault() {
         return mDefault;
     }
+
+    @Override
+    public String toString() {
+        return getNamespace() + "." + getName() + "[" + getDefault() + "]";
+    }
 }
diff --git a/core/java/android/flags/FeatureFlags.java b/core/java/android/flags/FeatureFlags.java
index 2c722a486e81..c7d9d57e68b5 100644
--- a/core/java/android/flags/FeatureFlags.java
+++ b/core/java/android/flags/FeatureFlags.java
@@ -17,19 +17,8 @@
 package android.flags;
 
 import android.annotation.NonNull;
-import android.content.Context;
-import android.os.RemoteException;
-import android.os.ServiceManager;
-import android.util.ArraySet;
-import android.util.Log;
 
-import com.android.internal.annotations.VisibleForTesting;
-
-import java.util.ArrayList;
-import java.util.HashMap;
 import java.util.HashSet;
-import java.util.List;
-import java.util.Map;
 import java.util.Set;
 
 /**
@@ -43,20 +32,14 @@ import java.util.Set;
  * @hide
  */
 public class FeatureFlags {
-    private static final String TAG = "FeatureFlags";
     private static FeatureFlags sInstance;
     private static final Object sInstanceLock = new Object();
 
-    private final Set<Flag<?>> mKnownFlags = new ArraySet<>();
-    private final Set<Flag<?>> mDirtyFlags = new ArraySet<>();
-
-    private IFeatureFlags mIFeatureFlags;
-    private final Map<String, Map<String, Boolean>> mBooleanOverrides = new HashMap<>();
     private final Set<ChangeListener> mListeners = new HashSet<>();
 
     /**
      * Obtain a per-process instance of FeatureFlags.
-     * @return A singleton instance of {@link FeatureFlags}.
+     * @return
      */
     @NonNull
     public static FeatureFlags getInstance() {
@@ -69,124 +52,7 @@ public class FeatureFlags {
         return sInstance;
     }
 
-    /** See {@link FeatureFlagsFake}. */
-    @VisibleForTesting(visibility = VisibleForTesting.Visibility.PRIVATE)
-    public static void setInstance(FeatureFlags instance) {
-        synchronized (sInstanceLock) {
-            sInstance = instance;
-        }
-    }
-
-    private final IFeatureFlagsCallback mIFeatureFlagsCallback = new IFeatureFlagsCallback.Stub() {
-        @Override
-        public void onFlagChange(SyncableFlag flag) {
-            for (Flag<?> f : mKnownFlags) {
-                if (flagEqualsSyncableFlag(f, flag)) {
-                    if (f instanceof DynamicFlag<?>) {
-                        if (f instanceof DynamicBooleanFlag) {
-                            String value = flag.getValue();
-                            if (value == null) {  // Null means any existing overrides were erased.
-                                value = ((DynamicBooleanFlag) f).getDefault().toString();
-                            }
-                            addBooleanOverride(flag.getNamespace(), flag.getName(), value);
-                        }
-                        FeatureFlags.this.onFlagChange((DynamicFlag<?>) f);
-                    }
-                    break;
-                }
-            }
-        }
-    };
-
-    private FeatureFlags() {
-        this(null);
-    }
-
-    @VisibleForTesting(visibility = VisibleForTesting.Visibility.PRIVATE)
-    public FeatureFlags(IFeatureFlags iFeatureFlags) {
-        mIFeatureFlags = iFeatureFlags;
-
-        if (mIFeatureFlags != null) {
-            try {
-                mIFeatureFlags.registerCallback(mIFeatureFlagsCallback);
-            } catch (RemoteException e) {
-                // Won't happen in tests.
-            }
-        }
-    }
-
-    /**
-     * Construct a new {@link BooleanFlag}.
-     *
-     * Use this instead of constructing a {@link BooleanFlag} directly, as it registers the flag
-     * with the internals of the flagging system.
-     */
-    @NonNull
-    public static BooleanFlag booleanFlag(
-            @NonNull String namespace, @NonNull String name, boolean def) {
-        return getInstance().addFlag(new BooleanFlag(namespace, name, def));
-    }
-
-    /**
-     * Construct a new {@link FusedOffFlag}.
-     *
-     * Use this instead of constructing a {@link FusedOffFlag} directly, as it registers the
-     * flag with the internals of the flagging system.
-     */
-    @NonNull
-    public static FusedOffFlag fusedOffFlag(@NonNull String namespace, @NonNull String name) {
-        return getInstance().addFlag(new FusedOffFlag(namespace, name));
-    }
-
-    /**
-     * Construct a new {@link FusedOnFlag}.
-     *
-     * Use this instead of constructing a {@link FusedOnFlag} directly, as it registers the flag
-     * with the internals of the flagging system.
-     */
-    @NonNull
-    public static FusedOnFlag fusedOnFlag(@NonNull String namespace, @NonNull String name) {
-        return getInstance().addFlag(new FusedOnFlag(namespace, name));
-    }
-
-    /**
-     * Construct a new {@link DynamicBooleanFlag}.
-     *
-     * Use this instead of constructing a {@link DynamicBooleanFlag} directly, as it registers
-     * the flag with the internals of the flagging system.
-     */
-    @NonNull
-    public static DynamicBooleanFlag dynamicBooleanFlag(
-            @NonNull String namespace, @NonNull String name, boolean def) {
-        return getInstance().addFlag(new DynamicBooleanFlag(namespace, name, def));
-    }
-
-    /**
-     * Add a listener to be alerted when a {@link DynamicFlag} changes.
-     *
-     * See also {@link #removeChangeListener(ChangeListener)}.
-     *
-     * @param listener The listener to add.
-     */
-    public void addChangeListener(@NonNull ChangeListener listener) {
-        mListeners.add(listener);
-    }
-
-    /**
-     * Remove a listener that was added earlier.
-     *
-     * See also {@link #addChangeListener(ChangeListener)}.
-     *
-     * @param listener The listener to remove.
-     */
-    public void removeChangeListener(@NonNull ChangeListener listener) {
-        mListeners.remove(listener);
-    }
-
-    protected void onFlagChange(@NonNull DynamicFlag<?> flag) {
-        for (ChangeListener l : mListeners) {
-            l.onFlagChanged(flag);
-        }
+    FeatureFlags() {
     }
 
     /**
@@ -197,7 +63,7 @@ public class FeatureFlags {
      * The first time a flag is read, its value is cached for the lifetime of the process.
      */
     public boolean isEnabled(@NonNull BooleanFlag flag) {
-        return getBooleanInternal(flag);
+        return flag.getDefault();
     }
 
     /**
@@ -224,138 +90,31 @@ public class FeatureFlags {
      * Can return a different value for the flag each time it is called if an override comes in.
      */
     public boolean isCurrentlyEnabled(@NonNull DynamicBooleanFlag flag) {
-        return getBooleanInternal(flag);
-    }
-
-    private boolean getBooleanInternal(Flag<Boolean> flag) {
-        sync();
-        Map<String, Boolean> ns = mBooleanOverrides.get(flag.getNamespace());
-        Boolean value = null;
-        if (ns != null) {
-            value = ns.get(flag.getName());
-        }
-        if (value == null) {
-            throw new IllegalStateException("Boolean flag being read but was not synced: " + flag);
-        }
-
-        return value;
-    }
-
-    private <T extends Flag<?>> T addFlag(T flag)  {
-        synchronized (FeatureFlags.class) {
-            mDirtyFlags.add(flag);
-            mKnownFlags.add(flag);
-        }
-        return flag;
-    }
-
-    protected void sync() {
-        synchronized (FeatureFlags.class) {
-            if (mDirtyFlags.isEmpty()) {
-                return;
-            }
-            syncInternal(mDirtyFlags);
-            mDirtyFlags.clear();
-        }
+        return flag.getDefault();
     }
 
     /**
-     * Called when new flags have been declared. Gives the implementation a chance to act on them.
+     * Add a listener to be alerted when a {@link DynamicFlag} changes.
+     *
+     * See also {@link #removeChangeListener(ChangeListener)}.
      *
-     * Guaranteed to be called from a synchronized, thread-safe context.
+     * @param listener The listener to add.
      */
-    protected void syncInternal(Set<Flag<?>> dirtyFlags) {
-        IFeatureFlags iFeatureFlags = bind();
-        List<SyncableFlag> syncableFlags = new ArrayList<>();
-        for (Flag<?> f : dirtyFlags) {
-            syncableFlags.add(flagToSyncableFlag(f));
-        }
-
-        List<SyncableFlag> serverFlags = List.of();  // Need to initialize the list with something.
-        try {
-            // New values come back from the service.
-            serverFlags = iFeatureFlags.syncFlags(syncableFlags);
-        } catch (RemoteException e) {
-            e.rethrowFromSystemServer();
-        }
-
-        for (Flag<?> f : dirtyFlags) {
-            boolean found = false;
-            for (SyncableFlag sf : serverFlags) {
-                if (flagEqualsSyncableFlag(f, sf)) {
-                    if (f instanceof BooleanFlag || f instanceof DynamicBooleanFlag) {
-                        addBooleanOverride(sf.getNamespace(), sf.getName(), sf.getValue());
-                    }
-                    found = true;
-                    break;
-                }
-            }
-            if (!found) {
-                if (f instanceof BooleanFlag) {
-                    addBooleanOverride(
-                            f.getNamespace(),
-                            f.getName(),
-                            ((BooleanFlag) f).getDefault() ? "true" : "false");
-                }
-            }
-        }
-    }
-
-    private void addBooleanOverride(String namespace, String name, String override) {
-        Map<String, Boolean> nsOverrides = mBooleanOverrides.get(namespace);
-        if (nsOverrides == null) {
-            nsOverrides = new HashMap<>();
-            mBooleanOverrides.put(namespace, nsOverrides);
-        }
-        nsOverrides.put(name, parseBoolean(override));
-    }
-
-    private SyncableFlag flagToSyncableFlag(Flag<?> f) {
-        return new SyncableFlag(
-                f.getNamespace(),
-                f.getName(),
-                f.getDefault().toString(),
-                f instanceof DynamicFlag<?>);
-    }
-
-    private IFeatureFlags bind() {
-        if (mIFeatureFlags == null) {
-            mIFeatureFlags = IFeatureFlags.Stub.asInterface(
-                    ServiceManager.getService(Context.FEATURE_FLAGS_SERVICE));
-            try {
-                mIFeatureFlags.registerCallback(mIFeatureFlagsCallback);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Failed to listen for flag changes!");
-            }
-        }
-
-        return mIFeatureFlags;
-    }
-
-    static boolean parseBoolean(String value) {
-        // Check for a truish string.
-        boolean result = value.equalsIgnoreCase("true")
-                || value.equals("1")
-                || value.equalsIgnoreCase("t")
-                || value.equalsIgnoreCase("on");
-        if (!result) {  // Expect a falsish string, else log an error.
-            if (!(value.equalsIgnoreCase("false")
-                    || value.equals("0")
-                    || value.equalsIgnoreCase("f")
-                    || value.equalsIgnoreCase("off"))) {
-                Log.e(TAG,
-                        "Tried parsing " + value + " as boolean but it doesn't look like one. "
-                                + "Value expected to be one of true|false, 1|0, t|f, on|off.");
-            }
-        }
-        return result;
+    public void addChangeListener(@NonNull ChangeListener listener) {
+        mListeners.add(listener);
     }
 
-    private static boolean flagEqualsSyncableFlag(Flag<?> f, SyncableFlag sf) {
-        return f.getName().equals(sf.getName()) && f.getNamespace().equals(sf.getNamespace());
+    /**
+     * Remove a listener that was added earlier.
+     *
+     * See also {@link #addChangeListener(ChangeListener)}.
+     *
+     * @param listener The listener to remove.
+     */
+    public void removeChangeListener(@NonNull ChangeListener listener) {
+        mListeners.remove(listener);
     }
 
-
     /**
      * A simpler listener that is alerted when a {@link DynamicFlag} changes.
      *
diff --git a/core/java/android/flags/FeatureFlagsFake.java b/core/java/android/flags/FeatureFlagsFake.java
index daedcdae0b5f..03bf2b6d33d2 100644
--- a/core/java/android/flags/FeatureFlagsFake.java
+++ b/core/java/android/flags/FeatureFlagsFake.java
@@ -18,98 +18,32 @@ package android.flags;
 
 import android.annotation.NonNull;
 
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.Map;
-import java.util.Set;
-
 /**
  * An implementation of {@link FeatureFlags} for testing.
- *
- * Before you read a flag from using this Fake, you must set that flag using
- * {@link #setFlagValue(BooleanFlagBase, boolean)}. This ensures that your tests are deterministic.
- *
- * If you are relying on {@link FeatureFlags#getInstance()} to access FeatureFlags in your code
- * under test, (instead of dependency injection), you can pass an instance of this fake to
- * {@link FeatureFlags#setInstance(FeatureFlags)}. Be sure to call that method again, passing null,
- * to ensure hermetic testing - you don't want static state persisting between your test methods.
- *
  * @hide
  */
 public class FeatureFlagsFake extends FeatureFlags {
-    private final Map<BooleanFlagBase, Boolean> mFlagValues = new HashMap<>();
-    private final Set<BooleanFlagBase> mReadFlags = new HashSet<>();
-
-    public FeatureFlagsFake(IFeatureFlags iFeatureFlags) {
-        super(iFeatureFlags);
+    public FeatureFlagsFake() {
+        super();
     }
 
     @Override
     public boolean isEnabled(@NonNull BooleanFlag flag) {
-        return requireFlag(flag);
+        return flag.getDefault();
     }
 
     @Override
     public boolean isEnabled(@NonNull FusedOffFlag flag) {
-        return requireFlag(flag);
+        return false;
     }
 
     @Override
     public boolean isEnabled(@NonNull FusedOnFlag flag) {
-        return requireFlag(flag);
+        return true;
     }
 
     @Override
     public boolean isCurrentlyEnabled(@NonNull DynamicBooleanFlag flag) {
-        return requireFlag(flag);
-    }
-
-    @Override
-    protected void syncInternal(Set<Flag<?>> dirtyFlags) {
-    }
-
-    /**
-     * Explicitly set a flag's value for reading in tests.
-     *
-     * You _must_ call this for every flag your code-under-test will read. Otherwise, an
-     * {@link IllegalStateException} will be thrown.
-     *
-     * You are able to set values for {@link FusedOffFlag} and {@link FusedOnFlag}, despite those
-     * flags having a fixed value at compile time, since unit tests should still test the state of
-     * those flags as both true and false. I.e. a flag that is off might be turned on in a future
-     * build or vice versa.
-     *
-     * You can not call this method _after_ a non-dynamic flag has been read. Non-dynamic flags
-     * are held stable in the system, so changing a value after reading would not match
-     * real-implementation behavior.
-     *
-     * Calling this method will trigger any {@link android.flags.FeatureFlags.ChangeListener}s that
-     * are registered for the supplied flag if the flag is a {@link DynamicFlag}.
-     *
-     * @param flag  The BooleanFlag that you want to set a value for.
-     * @param value The value that the flag should return when accessed.
-     */
-    public void setFlagValue(@NonNull BooleanFlagBase flag, boolean value) {
-        if (!(flag instanceof DynamicBooleanFlag) && mReadFlags.contains(flag)) {
-            throw new RuntimeException(
-                    "You can not set the value of a flag after it has been read. Tried to set "
-                            + flag + " to " + value + " but it already " + mFlagValues.get(flag));
-        }
-        mFlagValues.put(flag, value);
-        if (flag instanceof DynamicBooleanFlag) {
-            onFlagChange((DynamicFlag<?>) flag);
-        }
+        return flag.getDefault();
     }
-
-    private boolean requireFlag(BooleanFlagBase flag) {
-        if (!mFlagValues.containsKey(flag)) {
-            throw new IllegalStateException(
-                    "Tried to access " + flag + " in test but no overrided specified. You must "
-                            + "call #setFlagValue for each flag read in a test.");
-        }
-        mReadFlags.add(flag);
-
-        return mFlagValues.get(flag);
-    }
-
 }
diff --git a/core/java/android/flags/FusedOffFlag.java b/core/java/android/flags/FusedOffFlag.java
index 5f435beb2642..999d0f981780 100644
--- a/core/java/android/flags/FusedOffFlag.java
+++ b/core/java/android/flags/FusedOffFlag.java
@@ -17,7 +17,6 @@
 package android.flags;
 
 import android.annotation.NonNull;
-import android.provider.DeviceConfig;
 
 /**
  * A flag representing a false value.
@@ -26,13 +25,13 @@ import android.provider.DeviceConfig;
  *
  * @hide
  */
-public final class FusedOffFlag extends BooleanFlagBase {
-    /**
-     * @param namespace A namespace for this flag. See {@link DeviceConfig}.
-     * @param name      A name for this flag.
-     */
+public final class FusedOffFlag implements Flag<Boolean> {
+    private final String mNamespace;
+    private final String mName;
+
     FusedOffFlag(String namespace, String name) {
-        super(namespace, name);
+        mNamespace = namespace;
+        mName = name;
     }
 
     @Override
@@ -40,4 +39,22 @@ public final class FusedOffFlag extends BooleanFlagBase {
     public Boolean getDefault() {
         return false;
     }
+
+    @Override
+    @NonNull
+    public String getNamespace() {
+        return mNamespace;
+    }
+
+    @Override
+    @NonNull
+    public String getName() {
+        return mName;
+    }
+
+    @Override
+    @NonNull
+    public String toString() {
+        return getNamespace() + "." + getName() + "[false]";
+    }
 }
diff --git a/core/java/android/flags/FusedOnFlag.java b/core/java/android/flags/FusedOnFlag.java
index ea8d9b29b3ce..4f33bee8abe1 100644
--- a/core/java/android/flags/FusedOnFlag.java
+++ b/core/java/android/flags/FusedOnFlag.java
@@ -17,7 +17,6 @@
 package android.flags;
 
 import android.annotation.NonNull;
-import android.provider.DeviceConfig;
 
 /**
  * A flag representing a true value.
@@ -26,13 +25,13 @@ import android.provider.DeviceConfig;
  *
  * @hide
  */
-public final class FusedOnFlag extends BooleanFlagBase {
-    /**
-     * @param namespace A namespace for this flag. See {@link DeviceConfig}.
-     * @param name      A name for this flag.
-     */
+public final class FusedOnFlag implements Flag<Boolean> {
+    private final String mNamespace;
+    private final String mName;
+
     FusedOnFlag(String namespace, String name) {
-        super(namespace, name);
+        mNamespace = namespace;
+        mName = name;
     }
 
     @Override
@@ -40,4 +39,22 @@ public final class FusedOnFlag extends BooleanFlagBase {
     public Boolean getDefault() {
         return true;
     }
+
+    @Override
+    @NonNull
+    public String getNamespace() {
+        return mNamespace;
+    }
+
+    @Override
+    @NonNull
+    public String getName() {
+        return mName;
+    }
+
+    @Override
+    @NonNull
+    public String toString() {
+        return getNamespace() + "." + getName() + "[true]";
+    }
 }
diff --git a/core/java/android/flags/SyncableFlag.java b/core/java/android/flags/SyncableFlag.java
index 0b2a4d9e4f98..54c4c6d5fdf9 100644
--- a/core/java/android/flags/SyncableFlag.java
+++ b/core/java/android/flags/SyncableFlag.java
@@ -20,15 +20,18 @@ import android.annotation.NonNull;
 import android.os.Parcel;
 import android.os.Parcelable;
 
+import com.android.internal.annotations.VisibleForTesting;
+
 /**
  * @hide
  */
 public final class SyncableFlag implements Parcelable {
     private final String mNamespace;
     private final String mName;
-    private final String mValue;
+    private String mValue;
     private final boolean mDynamic;
 
+    @VisibleForTesting(visibility = VisibleForTesting.Visibility.PACKAGE)
     public SyncableFlag(
             @NonNull String namespace,
             @NonNull String name,
@@ -40,6 +43,10 @@ public final class SyncableFlag implements Parcelable {
         mDynamic = dynamic;
     }
 
+    public void setValue(@NonNull String value) {
+        mValue = value;
+    }
+
     @NonNull
     public String getNamespace() {
         return mNamespace;
diff --git a/core/tests/coretests/src/android/flags/FeatureFlagsTest.java b/core/tests/coretests/src/android/flags/FeatureFlagsTest.java
index 3fc94394d12c..dc6006a8e5fa 100644
--- a/core/tests/coretests/src/android/flags/FeatureFlagsTest.java
+++ b/core/tests/coretests/src/android/flags/FeatureFlagsTest.java
@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package android.flags;
 
 import static com.google.common.truth.Truth.assertThat;
@@ -21,135 +22,33 @@ import android.platform.test.annotations.Presubmit;
 
 import androidx.test.filters.SmallTest;
 
+import org.junit.After;
 import org.junit.Before;
+import org.junit.Ignore;
 import org.junit.Test;
-
-import java.util.List;
-import java.util.concurrent.atomic.AtomicBoolean;
-
+import org.mockito.MockitoAnnotations;
 
 @SmallTest
 @Presubmit
-public class FeatureFlagsTest {
-
-    IFeatureFlagsFake mIFeatureFlagsFake = new IFeatureFlagsFake();
-    FeatureFlags mFeatureFlags = new FeatureFlags(mIFeatureFlagsFake);
+public final class FeatureFlagsTest {
 
     @Before
     public void setup() {
-        FeatureFlags.setInstance(mFeatureFlags);
-    }
-
-    @Test
-    public void testFusedOff_Disabled() {
-        FusedOffFlag flag = FeatureFlags.fusedOffFlag("test", "a");
-        assertThat(mFeatureFlags.isEnabled(flag)).isFalse();
-    }
-
-    @Test
-    public void testFusedOn_Enabled() {
-        FusedOnFlag flag = FeatureFlags.fusedOnFlag("test", "a");
-        assertThat(mFeatureFlags.isEnabled(flag)).isTrue();
-    }
-
-    @Test
-    public void testBooleanFlag_DefaultDisabled() {
-        BooleanFlag flag = FeatureFlags.booleanFlag("test", "a", false);
-        assertThat(mFeatureFlags.isEnabled(flag)).isFalse();
-    }
-
-    @Test
-    public void testBooleanFlag_DefaultEnabled() {
-        BooleanFlag flag = FeatureFlags.booleanFlag("test", "a", true);
-        assertThat(mFeatureFlags.isEnabled(flag)).isTrue();
-    }
-
-    @Test
-    public void testDynamicBooleanFlag_DefaultDisabled() {
-        DynamicBooleanFlag flag = FeatureFlags.dynamicBooleanFlag("test", "a", false);
-        assertThat(mFeatureFlags.isCurrentlyEnabled(flag)).isFalse();
+        MockitoAnnotations.initMocks(this);
     }
 
-    @Test
-    public void testDynamicBooleanFlag_DefaultEnabled() {
-        DynamicBooleanFlag flag = FeatureFlags.dynamicBooleanFlag("test", "a", true);
-        assertThat(mFeatureFlags.isCurrentlyEnabled(flag)).isTrue();
+    @After
+    public void tearDown() {
     }
 
     @Test
-    public void testBooleanFlag_OverrideBeforeRead() {
-        BooleanFlag flag = FeatureFlags.booleanFlag("test", "a", false);
-        SyncableFlag syncableFlag = new SyncableFlag(
-                flag.getNamespace(), flag.getName(), "true", false);
-
-        mIFeatureFlagsFake.setFlagOverrides(List.of(syncableFlag));
-
-        assertThat(mFeatureFlags.isEnabled(flag)).isTrue();
+    public void testPass() {
+        assertThat(true).isTrue();
     }
 
+    @Ignore
     @Test
-    public void testFusedOffFlag_OverrideHasNoEffect() {
-        FusedOffFlag flag = FeatureFlags.fusedOffFlag("test", "a");
-        SyncableFlag syncableFlag = new SyncableFlag(
-                flag.getNamespace(), flag.getName(), "true", false);
-
-        mIFeatureFlagsFake.setFlagOverrides(List.of(syncableFlag));
-
-        assertThat(mFeatureFlags.isEnabled(flag)).isFalse();
-    }
-
-    @Test
-    public void testFusedOnFlag_OverrideHasNoEffect() {
-        FusedOnFlag flag = FeatureFlags.fusedOnFlag("test", "a");
-        SyncableFlag syncableFlag = new SyncableFlag(
-                flag.getNamespace(), flag.getName(), "false", false);
-
-        mIFeatureFlagsFake.setFlagOverrides(List.of(syncableFlag));
-
-        assertThat(mFeatureFlags.isEnabled(flag)).isTrue();
-    }
-
-    @Test
-    public void testDynamicFlag_OverrideBeforeRead() {
-        DynamicBooleanFlag flag = FeatureFlags.dynamicBooleanFlag("test", "a", false);
-        SyncableFlag syncableFlag = new SyncableFlag(
-                flag.getNamespace(), flag.getName(), "true", true);
-
-        mIFeatureFlagsFake.setFlagOverrides(List.of(syncableFlag));
-
-        // Changes to true
-        assertThat(mFeatureFlags.isCurrentlyEnabled(flag)).isTrue();
-    }
-
-    @Test
-    public void testDynamicFlag_OverrideAfterRead() {
-        DynamicBooleanFlag flag = FeatureFlags.dynamicBooleanFlag("test", "a", false);
-        SyncableFlag syncableFlag = new SyncableFlag(
-                flag.getNamespace(), flag.getName(), "true", true);
-
-        // Starts false
-        assertThat(mFeatureFlags.isCurrentlyEnabled(flag)).isFalse();
-
-        mIFeatureFlagsFake.setFlagOverrides(List.of(syncableFlag));
-
-        // Changes to true
-        assertThat(mFeatureFlags.isCurrentlyEnabled(flag)).isTrue();
-    }
-
-    @Test
-    public void testDynamicFlag_FiresListener() {
-        DynamicBooleanFlag flag = FeatureFlags.dynamicBooleanFlag("test", "a", false);
-        AtomicBoolean called = new AtomicBoolean(false);
-        FeatureFlags.ChangeListener listener = flag1 -> called.set(true);
-
-        mFeatureFlags.addChangeListener(listener);
-
-        SyncableFlag syncableFlag = new SyncableFlag(
-                flag.getNamespace(), flag.getName(), flag.getDefault().toString(), true);
-
-        mIFeatureFlagsFake.setFlagOverrides(List.of(syncableFlag));
-
-        // Fires listener.
-        assertThat(called.get()).isTrue();
+    public void testFail() {
+        assertThat(false).isTrue();
     }
 }
diff --git a/core/tests/coretests/src/android/flags/IFeatureFlagsFake.java b/core/tests/coretests/src/android/flags/IFeatureFlagsFake.java
deleted file mode 100644
index 70b65ce1eb57..000000000000
--- a/core/tests/coretests/src/android/flags/IFeatureFlagsFake.java
+++ /dev/null
@@ -1,63 +0,0 @@
-/*
- * Copyright (C) 2023 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.flags;
-
-import android.os.IBinder;
-import android.os.RemoteException;
-
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
-
-class IFeatureFlagsFake implements IFeatureFlags {
-
-    private final Set<IFeatureFlagsCallback> mCallbacks = new HashSet<>();
-
-    List<SyncableFlag> mOverrides;
-
-    @Override
-    public IBinder asBinder() {
-        return null;
-    }
-
-    @Override
-    public List<SyncableFlag> syncFlags(List<SyncableFlag> flagList) {
-        return mOverrides == null ? flagList : mOverrides;
-    }
-
-    @Override
-    public void registerCallback(IFeatureFlagsCallback callback) {
-        mCallbacks.add(callback);
-    }
-
-    @Override
-    public void unregisterCallback(IFeatureFlagsCallback callback) {
-        mCallbacks.remove(callback);
-    }
-
-    public void setFlagOverrides(List<SyncableFlag> flagList) {
-        mOverrides = flagList;
-        for (SyncableFlag sf : flagList) {
-            for (IFeatureFlagsCallback cb : mCallbacks) {
-                try {
-                    cb.onFlagChange(sf);
-                } catch (RemoteException e) {
-                    // does not happen in fakes.
-                }
-            }
-        }
-    }
-}
diff --git a/services/flags/java/com/android/server/flags/DynamicFlagBinderDelegate.java b/services/flags/java/com/android/server/flags/DynamicFlagBinderDelegate.java
index 8da5aae6abdd..322a52bf01cc 100644
--- a/services/flags/java/com/android/server/flags/DynamicFlagBinderDelegate.java
+++ b/services/flags/java/com/android/server/flags/DynamicFlagBinderDelegate.java
@@ -118,9 +118,9 @@ class DynamicFlagBinderDelegate {
         mFlagStore.setChangeCallback(mFlagChangeCallback);
     }
 
-    SyncableFlag syncDynamicFlag(int pid, SyncableFlag sf) {
+    void syncDynamicFlag(int pid, SyncableFlag sf) {
         if (!sf.isDynamic()) {
-            return sf;
+            return;
         }
 
         String ns = sf.getNamespace();
@@ -162,7 +162,7 @@ class DynamicFlagBinderDelegate {
         // to something.
         data.setDefaultValue(sf.getValue());
 
-        return new SyncableFlag(sf.getNamespace(), sf.getName(), value, true);
+        sf.setValue(value);
     }
 
 
diff --git a/services/flags/java/com/android/server/flags/FeatureFlagsBinder.java b/services/flags/java/com/android/server/flags/FeatureFlagsBinder.java
index 86b464dbdf5d..dc97fde758dc 100644
--- a/services/flags/java/com/android/server/flags/FeatureFlagsBinder.java
+++ b/services/flags/java/com/android/server/flags/FeatureFlagsBinder.java
@@ -25,7 +25,6 @@ import android.os.Build;
 import android.os.ParcelFileDescriptor;
 
 import java.io.FileOutputStream;
-import java.util.ArrayList;
 import java.util.List;
 
 class FeatureFlagsBinder extends IFeatureFlags.Stub {
@@ -53,13 +52,11 @@ class FeatureFlagsBinder extends IFeatureFlags.Stub {
     @Override
     public List<SyncableFlag> syncFlags(List<SyncableFlag> incomingFlags) {
         int pid = getCallingPid();
-        List<SyncableFlag> outputFlags = new ArrayList<>();
         for (SyncableFlag sf : incomingFlags) {
             String ns = sf.getNamespace();
             String name = sf.getName();
-            SyncableFlag outFlag;
             if (sf.isDynamic()) {
-                outFlag = mDynamicFlagDelegate.syncDynamicFlag(pid, sf);
+                mDynamicFlagDelegate.syncDynamicFlag(pid, sf);
             } else {
                 synchronized (mFlagCache) {
                     String value = mFlagCache.getOrNull(ns, name);
@@ -68,12 +65,11 @@ class FeatureFlagsBinder extends IFeatureFlags.Stub {
                         value = overrideValue != null ? overrideValue : sf.getValue();
                         mFlagCache.setIfChanged(ns, name, value);
                     }
-                    outFlag = new SyncableFlag(sf.getNamespace(), sf.getName(), value, false);
+                    sf.setValue(value);
                 }
             }
-            outputFlags.add(outFlag);
         }
-        return outputFlags;
+        return incomingFlags;
     }
 
     @SystemApi