Be more paranoid about threading in MediaSessionRecord

This makes copies of objects with bundles before posting to another
thread and is more aggressive about locking before making assignments
of mutable objects.

bug:17692568
Change-Id: I28e8229718b862c485e870fd2ca06a3a18a7c454

Author: RoboErikG

services/core/java/com/android/server/media/MediaSessionRecord.java

@@ -615,7 +615,10 @@ private void pushSessionDestroyed() {
     }
 
     private PlaybackState getStateWithUpdatedPosition() {
-        PlaybackState state = mPlaybackState;
+        PlaybackState state;
+        synchronized (mLock) {
+            state = mPlaybackState;
+        }
         long duration = -1;
         if (mMetadata != null && mMetadata.containsKey(MediaMetadata.METADATA_KEY_DURATION)) {
             duration = mMetadata.getLong(MediaMetadata.METADATA_KEY_DURATION);
@@ -674,7 +677,8 @@ public void destroy() {
 
         @Override
         public void sendEvent(String event, Bundle data) {
-            mHandler.post(MessageHandler.MSG_SEND_EVENT, event, data);
+            mHandler.post(MessageHandler.MSG_SEND_EVENT, event,
+                    data == null ? null : new Bundle(data));
         }
 
         @Override
@@ -712,7 +716,11 @@ public void setLaunchPendingIntent(PendingIntent pi) {
 
         @Override
         public void setMetadata(MediaMetadata metadata) {
-            mMetadata = metadata;
+            // Make a copy of the metadata as the underlying bundle may be
+            // modified on this thread.
+            synchronized (mLock) {
+                mMetadata = metadata == null ? null : new MediaMetadata.Builder(metadata).build();
+            }
             mHandler.post(MessageHandler.MSG_UPDATE_METADATA);
         }
 
@@ -723,14 +731,18 @@ public void setPlaybackState(PlaybackState state) {
             if (MediaSession.isActiveState(oldState) && newState == PlaybackState.STATE_PAUSED) {
                 mLastActiveTime = SystemClock.elapsedRealtime();
             }
-            mPlaybackState = state;
+            synchronized (mLock) {
+                mPlaybackState = state;
+            }
             mService.onSessionPlaystateChange(MediaSessionRecord.this, oldState, newState);
             mHandler.post(MessageHandler.MSG_UPDATE_PLAYBACK_STATE);
         }
 
         @Override
         public void setQueue(ParceledListSlice queue) {
-            mQueue = queue;
+            synchronized (mLock) {
+                mQueue = queue;
+            }
             mHandler.post(MessageHandler.MSG_UPDATE_QUEUE);
         }
 
@@ -742,7 +754,9 @@ public void setQueueTitle(CharSequence title) {
 
         @Override
         public void setExtras(Bundle extras) {
-            mExtras = extras;
+            synchronized (mLock) {
+                mExtras = extras == null ? null : new Bundle(extras);
+            }
             mHandler.post(MessageHandler.MSG_UPDATE_EXTRAS);
         }
 
@@ -1118,7 +1132,9 @@ public void sendCustomAction(String action, Bundle args)
 
         @Override
         public MediaMetadata getMetadata() {
-            return mMetadata;
+            synchronized (mLock) {
+                return mMetadata;
+            }
         }
 
         @Override
@@ -1128,7 +1144,9 @@ public PlaybackState getPlaybackState() {
 
         @Override
         public ParceledListSlice getQueue() {
-            return mQueue;
+            synchronized (mLock) {
+                return mQueue;
+            }
         }
 
         @Override
@@ -1138,7 +1156,9 @@ public CharSequence getQueueTitle() {
 
         @Override
         public Bundle getExtras() {
-            return mExtras;
+            synchronized (mLock) {
+                return mExtras;
+            }
         }
 
         @Override