Use @UsesReflection for LocalTransport keep rules

Prefer the @UsesReflection annotation to generate the keep rules
necessary to preserve LocalTransport derived class names. These
class names should be kept as they are used to generate a name that
may be referenced by other packages. Other classes currently in the
proguard config are automatically kept by manifest-generated keep
rules, or are otherwise unnecessary.

This change is effectively a no-op under the current shrinking
configuration for both LocalTransport and EncryptedLocalTransport. If
obfuscation is enabled, this annotation will ensure continued
correctness.

Bug: 248580093
Test: m + ensure all classes kept
Change-Id: I867693861e5b1ca9765c926d676c0b18b16cc340

5 files changed, 11 insertions, 13 deletions

diff --git a/packages/EncryptedLocalTransport/Android.bp b/packages/EncryptedLocalTransport/Android.bp
index 09e563076c95..9ae6d9648979 100644
--- a/packages/EncryptedLocalTransport/Android.bp
+++ b/packages/EncryptedLocalTransport/Android.bp
@@ -27,9 +27,6 @@ android_app {
     name: "EncryptedLocalTransport",
     defaults: ["platform_app_defaults"],
     srcs: ["src/**/*.java"],
-    optimize: {
-        proguard_flags_files: ["proguard.flags"],
-    },
     static_libs: ["LocalTransport"],
     platform_apis: true,
     certificate: "platform",
diff --git a/packages/EncryptedLocalTransport/proguard.flags b/packages/EncryptedLocalTransport/proguard.flags
deleted file mode 100644
index e4ce3c524e35..000000000000
--- a/packages/EncryptedLocalTransport/proguard.flags
+++ /dev/null
@@ -1,2 +0,0 @@
--keep class com.android.localTransport.EncryptedLocalTransport
--keep class com.android.localTransport.EncryptedLocalTransportService
diff --git a/packages/LocalTransport/Android.bp b/packages/LocalTransport/Android.bp
index d4fa1915a140..e7a273b83a7d 100644
--- a/packages/LocalTransport/Android.bp
+++ b/packages/LocalTransport/Android.bp
@@ -27,9 +27,7 @@ android_app {
     name: "LocalTransport",
     defaults: ["platform_app_defaults"],
     srcs: ["src/**/*.java"],
-    optimize: {
-        proguard_flags_files: ["proguard.flags"],
-    },
+    libs: ["keepanno-annotations"],
     platform_apis: true,
     certificate: "platform",
     privileged: true,
diff --git a/packages/LocalTransport/proguard.flags b/packages/LocalTransport/proguard.flags
deleted file mode 100644
index c1f51b892d40..000000000000
--- a/packages/LocalTransport/proguard.flags
+++ /dev/null
@@ -1,5 +0,0 @@
--keep class com.android.localTransport.LocalTransport
--keep class com.android.localTransport.LocalTransportParameters
--keep class com.android.localTransport.LocalTransportService
-
-
diff --git a/packages/LocalTransport/src/com/android/localtransport/LocalTransport.java b/packages/LocalTransport/src/com/android/localtransport/LocalTransport.java
index 4344e9401fc9..6540cc060bc2 100644
--- a/packages/LocalTransport/src/com/android/localtransport/LocalTransport.java
+++ b/packages/LocalTransport/src/com/android/localtransport/LocalTransport.java
@@ -35,6 +35,9 @@ import android.util.ArrayMap;
 import android.util.Base64;
 import android.util.Log;
 
+import com.android.tools.r8.keepanno.annotations.KeepTarget;
+import com.android.tools.r8.keepanno.annotations.UsesReflection;
+
 import libcore.io.IoUtils;
 
 import java.io.BufferedOutputStream;
@@ -122,6 +125,13 @@ public class LocalTransport extends BackupTransport {
         return mParameters;
     }
 
+
+    @UsesReflection({
+            // As the runtime class name is used to generate the returned name, and the returned
+            // name may be used used with reflection, generate the necessary keep rules.
+            @KeepTarget(classConstant = LocalTransport.class),
+            @KeepTarget(extendsClassConstant = LocalTransport.class)
+    })
     @Override
     public String name() {
         return new ComponentName(mContext, this.getClass()).flattenToShortString();