Merge "Restore the selected route when an app starts to make sound" into oc-dr1-dev
diff --git a/media/java/android/media/IMediaRouterClient.aidl b/media/java/android/media/IMediaRouterClient.aidl
index 9640dcb..08344f1 100644
--- a/media/java/android/media/IMediaRouterClient.aidl
+++ b/media/java/android/media/IMediaRouterClient.aidl
@@ -21,4 +21,5 @@
  */
 oneway interface IMediaRouterClient {
     void onStateChanged();
+    void onRestoreRoute();
 }
diff --git a/media/java/android/media/IMediaRouterService.aidl b/media/java/android/media/IMediaRouterService.aidl
index f8f5fdf..3308fc9 100644
--- a/media/java/android/media/IMediaRouterService.aidl
+++ b/media/java/android/media/IMediaRouterService.aidl
@@ -27,6 +27,7 @@
     void unregisterClient(IMediaRouterClient client);
 
     MediaRouterClientState getState(IMediaRouterClient client);
+    boolean isPlaybackActive(IMediaRouterClient client);
 
     void setDiscoveryRequest(IMediaRouterClient client, int routeTypes, boolean activeScan);
     void setSelectedRoute(IMediaRouterClient client, String routeId, boolean explicit);
diff --git a/media/java/android/media/MediaRouter.java b/media/java/android/media/MediaRouter.java
index 8caba81..80a0315 100644
--- a/media/java/android/media/MediaRouter.java
+++ b/media/java/android/media/MediaRouter.java
@@ -88,6 +88,7 @@
         RouteInfo mBluetoothA2dpRoute;
 
         RouteInfo mSelectedRoute;
+        RouteInfo mSystemAudioRoute;
 
         final boolean mCanConfigureWifiDisplays;
         boolean mActivelyScanningWifiDisplays;
@@ -149,6 +150,7 @@
             }
 
             addRouteStatic(mDefaultAudioVideo);
+            mSystemAudioRoute = mDefaultAudioVideo;
 
             // This will select the active wifi display route if there is one.
             updateWifiDisplayStatus(mDisplayService.getWifiDisplayStatus());
@@ -197,8 +199,8 @@
                 } else {
                     name = com.android.internal.R.string.default_audio_route_name;
                 }
-                sStatic.mDefaultAudioVideo.mNameResId = name;
-                dispatchRouteChanged(sStatic.mDefaultAudioVideo);
+                mDefaultAudioVideo.mNameResId = name;
+                dispatchRouteChanged(mDefaultAudioVideo);
                 updated = true;
             }
 
@@ -207,22 +209,28 @@
             if (!TextUtils.equals(newRoutes.bluetoothName, mCurAudioRoutesInfo.bluetoothName)) {
                 mCurAudioRoutesInfo.bluetoothName = newRoutes.bluetoothName;
                 if (mCurAudioRoutesInfo.bluetoothName != null) {
-                    if (sStatic.mBluetoothA2dpRoute == null) {
-                        final RouteInfo info = new RouteInfo(sStatic.mSystemCategory);
+                    if (mBluetoothA2dpRoute == null) {
+                        // BT connected
+                        final RouteInfo info = new RouteInfo(mSystemCategory);
                         info.mName = mCurAudioRoutesInfo.bluetoothName;
-                        info.mDescription = sStatic.mResources.getText(
+                        info.mDescription = mResources.getText(
                                 com.android.internal.R.string.bluetooth_a2dp_audio_route_name);
                         info.mSupportedTypes = ROUTE_TYPE_LIVE_AUDIO;
                         info.mDeviceType = RouteInfo.DEVICE_TYPE_BLUETOOTH;
-                        sStatic.mBluetoothA2dpRoute = info;
-                        addRouteStatic(sStatic.mBluetoothA2dpRoute);
+                        mBluetoothA2dpRoute = info;
+                        addRouteStatic(mBluetoothA2dpRoute);
+                        mSystemAudioRoute = mBluetoothA2dpRoute;
+                        selectRouteStatic(ROUTE_TYPE_LIVE_AUDIO, mSystemAudioRoute, false);
                     } else {
-                        sStatic.mBluetoothA2dpRoute.mName = mCurAudioRoutesInfo.bluetoothName;
-                        dispatchRouteChanged(sStatic.mBluetoothA2dpRoute);
+                        mBluetoothA2dpRoute.mName = mCurAudioRoutesInfo.bluetoothName;
+                        dispatchRouteChanged(mBluetoothA2dpRoute);
                     }
-                } else if (sStatic.mBluetoothA2dpRoute != null) {
-                    removeRouteStatic(sStatic.mBluetoothA2dpRoute);
-                    sStatic.mBluetoothA2dpRoute = null;
+                } else if (mBluetoothA2dpRoute != null) {
+                    // BT disconnected
+                    removeRouteStatic(mBluetoothA2dpRoute);
+                    mBluetoothA2dpRoute = null;
+                    mSystemAudioRoute = mDefaultAudioVideo;
+                    selectRouteStatic(ROUTE_TYPE_LIVE_AUDIO, mSystemAudioRoute, false);
                 }
                 updated = true;
             }
@@ -230,11 +238,13 @@
             if (mBluetoothA2dpRoute != null) {
                 final boolean a2dpEnabled = isBluetoothA2dpOn();
                 if (mSelectedRoute == mBluetoothA2dpRoute && !a2dpEnabled) {
-                    selectRouteStatic(ROUTE_TYPE_LIVE_AUDIO, mDefaultAudioVideo, false);
+                    // A2DP off
+                    mSystemAudioRoute = mDefaultAudioVideo;
                     updated = true;
                 } else if ((mSelectedRoute == mDefaultAudioVideo || mSelectedRoute == null) &&
                         a2dpEnabled) {
-                    selectRouteStatic(ROUTE_TYPE_LIVE_AUDIO, mBluetoothA2dpRoute, false);
+                    // A2DP on or BT connected
+                    mSystemAudioRoute = mBluetoothA2dpRoute;
                     updated = true;
                 }
             }
@@ -471,7 +481,7 @@
         }
 
         RouteInfo makeGlobalRoute(MediaRouterClientState.RouteInfo globalRoute) {
-            RouteInfo route = new RouteInfo(sStatic.mSystemCategory);
+            RouteInfo route = new RouteInfo(mSystemCategory);
             route.mGlobalRouteId = globalRoute.id;
             route.mName = globalRoute.name;
             route.mDescription = globalRoute.description;
@@ -567,6 +577,17 @@
             return null;
         }
 
+        boolean isPlaybackActive() {
+            if (mClient != null) {
+                try {
+                    return mMediaRouterService.isPlaybackActive(mClient);
+                } catch (RemoteException ex) {
+                    Log.e(TAG, "Unable to retrieve playback active state.", ex);
+                }
+            }
+            return false;
+        }
+
         final class Client extends IMediaRouterClient.Stub {
             @Override
             public void onStateChanged() {
@@ -579,6 +600,19 @@
                     }
                 });
             }
+
+            @Override
+            public void onRestoreRoute() {
+                if ((mSelectedRoute != mDefaultAudioVideo && mSelectedRoute != mBluetoothA2dpRoute)
+                        || mSelectedRoute == mSystemAudioRoute) {
+                    return;
+                }
+                try {
+                    sStatic.mAudioService.setBluetoothA2dpOn(mSelectedRoute == mBluetoothA2dpRoute);
+                } catch (RemoteException e) {
+                    Log.e(TAG, "Error changing Bluetooth A2DP state", e);
+                }
+            }
         }
     }
 
@@ -909,7 +943,12 @@
         Log.v(TAG, "Selecting route: " + route);
         assert(route != null);
         final RouteInfo oldRoute = sStatic.mSelectedRoute;
-        if (oldRoute == route) return;
+        boolean wasDefaultOrBluetoothRoute = (oldRoute == sStatic.mDefaultAudioVideo
+                || oldRoute == sStatic.mBluetoothA2dpRoute);
+        if (oldRoute == route
+                && (!wasDefaultOrBluetoothRoute || oldRoute == sStatic.mSystemAudioRoute)) {
+            return;
+        }
         if (!route.matchesTypes(types)) {
             Log.w(TAG, "selectRoute ignored; cannot select route with supported types " +
                     typesToString(route.getSupportedTypes()) + " into route types " +
@@ -918,8 +957,8 @@
         }
 
         final RouteInfo btRoute = sStatic.mBluetoothA2dpRoute;
-        if (btRoute != null && (types & ROUTE_TYPE_LIVE_AUDIO) != 0 &&
-                (route == btRoute || route == sStatic.mDefaultAudioVideo)) {
+        if (sStatic.isPlaybackActive() && btRoute != null && (types & ROUTE_TYPE_LIVE_AUDIO) != 0
+                && (route == btRoute || route == sStatic.mDefaultAudioVideo)) {
             try {
                 sStatic.mAudioService.setBluetoothA2dpOn(route == btRoute);
                 // TODO: Remove the following logging when no longer needed.
diff --git a/services/core/java/com/android/server/media/AudioPlaybackMonitor.java b/services/core/java/com/android/server/media/AudioPlaybackMonitor.java
index c6dc11c..f6f7676 100644
--- a/services/core/java/com/android/server/media/AudioPlaybackMonitor.java
+++ b/services/core/java/com/android/server/media/AudioPlaybackMonitor.java
@@ -31,17 +31,22 @@
 import java.io.PrintWriter;
 import java.util.ArrayList;
 import java.util.HashSet;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 
 /**
- * Monitors changes in audio playback and notify the newly started audio playback through the
- * {@link OnAudioPlaybackStartedListener}.
+ * Monitors changes in audio playback, and notify the newly started audio playback through the
+ * {@link OnAudioPlaybackStartedListener} and the activeness change through the
+ * {@link OnAudioPlaybackActiveStateListener}.
  */
 class AudioPlaybackMonitor extends IPlaybackConfigDispatcher.Stub {
     private static boolean DEBUG = MediaSessionService.DEBUG;
     private static String TAG = "AudioPlaybackMonitor";
 
+    private static AudioPlaybackMonitor sInstance;
+
     /**
      * Called when audio playback is started for a given UID.
      */
@@ -49,22 +54,36 @@
         void onAudioPlaybackStarted(int uid);
     }
 
+    /**
+     * Called when audio player state is changed.
+     */
+    interface OnAudioPlayerActiveStateChangedListener {
+        void onAudioPlayerActiveStateChanged(int uid, boolean active);
+    }
+
     private final Object mLock = new Object();
     private final Context mContext;
-    private final OnAudioPlaybackStartedListener mListener;
-
-    private Set<Integer> mActiveAudioPlaybackPlayerInterfaceIds = new HashSet<>();
-    private Set<Integer> mActiveAudioPlaybackClientUids = new HashSet<>();
+    private final List<OnAudioPlaybackStartedListener> mAudioPlaybackStartedListeners
+            = new ArrayList<>();
+    private final List<OnAudioPlayerActiveStateChangedListener>
+            mAudioPlayerActiveStateChangedListeners = new ArrayList<>();
+    private final Map<Integer, Integer> mAudioPlaybackStates = new HashMap<>();
+    private final Set<Integer> mActiveAudioPlaybackClientUids = new HashSet<>();
 
     // Sorted array of UIDs that had active audio playback. (i.e. playing an audio/video)
     // The UID whose audio playback becomes active at the last comes first.
     // TODO(b/35278867): Find and use unique identifier for apps because apps may share the UID.
     private final IntArray mSortedAudioPlaybackClientUids = new IntArray();
 
-    AudioPlaybackMonitor(Context context, IAudioService audioService,
-            OnAudioPlaybackStartedListener listener) {
+    static AudioPlaybackMonitor getInstance(Context context, IAudioService audioService) {
+        if (sInstance == null) {
+            sInstance = new AudioPlaybackMonitor(context, audioService);
+        }
+        return sInstance;
+    }
+
+    private AudioPlaybackMonitor(Context context, IAudioService audioService) {
         mContext = context;
-        mListener = listener;
         try {
             audioService.registerPlaybackCallback(this);
         } catch (RemoteException e) {
@@ -84,9 +103,12 @@
     public void dispatchPlaybackConfigChange(List<AudioPlaybackConfiguration> configs) {
         final long token = Binder.clearCallingIdentity();
         try {
-            Set<Integer> newActiveAudioPlaybackPlayerInterfaceIds = new HashSet<>();
             List<Integer> newActiveAudioPlaybackClientUids = new ArrayList<>();
+            List<OnAudioPlayerActiveStateChangedListener> audioPlayerActiveStateChangedListeners;
+            List<OnAudioPlaybackStartedListener> audioPlaybackStartedListeners;
             synchronized (mLock) {
+                // Update mActiveAudioPlaybackClientUids and mSortedAudioPlaybackClientUids,
+                // and find newly activated audio playbacks.
                 mActiveAudioPlaybackClientUids.clear();
                 for (AudioPlaybackConfiguration config : configs) {
                     // Ignore inactive (i.e. not playing) or PLAYER_TYPE_JAM_SOUNDPOOL
@@ -94,16 +116,14 @@
                     // playback.
                     // Note that we shouldn't ignore PLAYER_TYPE_UNKNOWN because it might be OEM
                     // specific audio/video players.
-                    if (!config.isActive()
-                            || config.getPlayerType()
+                    if (!config.isActive() || config.getPlayerType()
                             == AudioPlaybackConfiguration.PLAYER_TYPE_JAM_SOUNDPOOL) {
                         continue;
                     }
-                    mActiveAudioPlaybackClientUids.add(config.getClientUid());
 
-                    newActiveAudioPlaybackPlayerInterfaceIds.add(config.getPlayerInterfaceId());
-                    if (!mActiveAudioPlaybackPlayerInterfaceIds.contains(
-                            config.getPlayerInterfaceId())) {
+                    mActiveAudioPlaybackClientUids.add(config.getClientUid());
+                    Integer oldState = mAudioPlaybackStates.get(config.getPlayerInterfaceId());
+                    if (!isActiveState(oldState)) {
                         if (DEBUG) {
                             Log.d(TAG, "Found a new active media playback. " +
                                     AudioPlaybackConfiguration.toLogFriendlyString(config));
@@ -120,11 +140,32 @@
                         mSortedAudioPlaybackClientUids.add(0, config.getClientUid());
                     }
                 }
-                mActiveAudioPlaybackPlayerInterfaceIds.clear();
-                mActiveAudioPlaybackPlayerInterfaceIds = newActiveAudioPlaybackPlayerInterfaceIds;
+                audioPlayerActiveStateChangedListeners = new ArrayList<>(
+                        mAudioPlayerActiveStateChangedListeners);
+                audioPlaybackStartedListeners = new ArrayList<>(mAudioPlaybackStartedListeners);
             }
+            // Notify the change of audio playback states.
+            for (AudioPlaybackConfiguration config : configs) {
+                boolean wasActive = isActiveState(
+                        mAudioPlaybackStates.get(config.getPlayerInterfaceId()));
+                boolean isActive = config.isActive();
+                if (wasActive != isActive) {
+                    for (OnAudioPlayerActiveStateChangedListener listener
+                            : audioPlayerActiveStateChangedListeners) {
+                        listener.onAudioPlayerActiveStateChanged(config.getClientUid(),
+                                isActive);
+                    }
+                }
+            }
+            // Notify the start of audio playback
             for (int uid : newActiveAudioPlaybackClientUids) {
-                mListener.onAudioPlaybackStarted(uid);
+                for (OnAudioPlaybackStartedListener listener : audioPlaybackStartedListeners) {
+                    listener.onAudioPlaybackStarted(uid);
+                }
+            }
+            mAudioPlaybackStates.clear();
+            for (AudioPlaybackConfiguration config : configs) {
+                mAudioPlaybackStates.put(config.getPlayerInterfaceId(), config.getPlayerState());
             }
         } finally {
             Binder.restoreCallingIdentity(token);
@@ -132,6 +173,44 @@
     }
 
     /**
+     * Registers OnAudioPlaybackStartedListener.
+     */
+    public void registerOnAudioPlaybackStartedListener(OnAudioPlaybackStartedListener listener) {
+        synchronized (mLock) {
+            mAudioPlaybackStartedListeners.add(listener);
+        }
+    }
+
+    /**
+     * Unregisters OnAudioPlaybackStartedListener.
+     */
+    public void unregisterOnAudioPlaybackStartedListener(OnAudioPlaybackStartedListener listener) {
+        synchronized (mLock) {
+            mAudioPlaybackStartedListeners.remove(listener);
+        }
+    }
+
+    /**
+     * Registers OnAudioPlayerActiveStateChangedListener.
+     */
+    public void registerOnAudioPlayerActiveStateChangedListener(
+            OnAudioPlayerActiveStateChangedListener listener) {
+        synchronized (mLock) {
+            mAudioPlayerActiveStateChangedListeners.add(listener);
+        }
+    }
+
+    /**
+     * Unregisters OnAudioPlayerActiveStateChangedListener.
+     */
+    public void unregisterOnAudioPlayerActiveStateChangedListener(
+            OnAudioPlayerActiveStateChangedListener listener) {
+        synchronized (mLock) {
+            mAudioPlayerActiveStateChangedListeners.remove(listener);
+        }
+    }
+
+    /**
      * Returns the sorted list of UIDs that have had active audio playback. (i.e. playing an
      * audio/video) The UID whose audio playback becomes active at the last comes first.
      */
@@ -167,7 +246,8 @@
                 if (mSortedAudioPlaybackClientUids.get(i) == mediaButtonSessionUid) {
                     break;
                 }
-                if (userId == UserHandle.getUserId(mSortedAudioPlaybackClientUids.get(i))) {
+                int uid = mSortedAudioPlaybackClientUids.get(i);
+                if (userId == UserHandle.getUserId(uid) && !isPlaybackActive(uid)) {
                     // Clean up unnecessary UIDs.
                     // It doesn't need to be managed profile aware because it's just to prevent
                     // the list from increasing indefinitely. The media button session updating
@@ -198,4 +278,8 @@
             }
         }
     }
+
+    private boolean isActiveState(Integer state) {
+        return state != null && state.equals(AudioPlaybackConfiguration.PLAYER_STATE_STARTED);
+    }
 }
diff --git a/services/core/java/com/android/server/media/MediaRouterService.java b/services/core/java/com/android/server/media/MediaRouterService.java
index d1fa5ef..5ba8f48 100644
--- a/services/core/java/com/android/server/media/MediaRouterService.java
+++ b/services/core/java/com/android/server/media/MediaRouterService.java
@@ -18,6 +18,7 @@
 
 import com.android.internal.util.DumpUtils;
 import com.android.server.Watchdog;
+import com.android.server.media.AudioPlaybackMonitor.OnAudioPlayerActiveStateChangedListener;
 
 import android.Manifest;
 import android.app.ActivityManager;
@@ -26,7 +27,10 @@
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.content.pm.PackageManager;
+import android.media.AudioRoutesInfo;
 import android.media.AudioSystem;
+import android.media.IAudioRoutesObserver;
+import android.media.IAudioService;
 import android.media.IMediaRouterClient;
 import android.media.IMediaRouterService;
 import android.media.MediaRouter;
@@ -39,9 +43,12 @@
 import android.os.Looper;
 import android.os.Message;
 import android.os.RemoteException;
+import android.os.ServiceManager;
 import android.os.SystemClock;
+import android.os.UserHandle;
 import android.text.TextUtils;
 import android.util.ArrayMap;
+import android.util.IntArray;
 import android.util.Log;
 import android.util.Slog;
 import android.util.SparseArray;
@@ -89,10 +96,54 @@
     private final ArrayMap<IBinder, ClientRecord> mAllClientRecords =
             new ArrayMap<IBinder, ClientRecord>();
     private int mCurrentUserId = -1;
+    private boolean mHasBluetoothRoute = false;
+    private final IAudioService mAudioService;
+    private final AudioPlaybackMonitor mAudioPlaybackMonitor;
 
     public MediaRouterService(Context context) {
         mContext = context;
         Watchdog.getInstance().addMonitor(this);
+
+        mAudioService = IAudioService.Stub.asInterface(
+                ServiceManager.getService(Context.AUDIO_SERVICE));
+
+        mAudioPlaybackMonitor = AudioPlaybackMonitor.getInstance(context, mAudioService);
+        mAudioPlaybackMonitor.registerOnAudioPlayerActiveStateChangedListener(
+                new AudioPlaybackMonitor.OnAudioPlayerActiveStateChangedListener() {
+            @Override
+            public void onAudioPlayerActiveStateChanged(int uid, boolean active) {
+                if (active) {
+                    restoreRoute(uid);
+                } else {
+                    IntArray sortedAudioPlaybackClientUids =
+                            mAudioPlaybackMonitor.getSortedAudioPlaybackClientUids();
+                    boolean restored = false;
+                    for (int i = 0; i < sortedAudioPlaybackClientUids.size(); i++) {
+                        if (mAudioPlaybackMonitor.isPlaybackActive(
+                                sortedAudioPlaybackClientUids.get(i))) {
+                            restoreRoute(sortedAudioPlaybackClientUids.get(i));
+                            restored = true;
+                            break;
+                        }
+                    }
+                    if (!restored) {
+                        restoreBluetoothA2dp();
+                    }
+                }
+            }
+        });
+        AudioRoutesInfo audioRoutes = null;
+        try {
+            audioRoutes = mAudioService.startWatchingRoutes(new IAudioRoutesObserver.Stub() {
+                @Override
+                public void dispatchAudioRoutesChanged(final AudioRoutesInfo newRoutes) {
+                    mHasBluetoothRoute = newRoutes.bluetoothName != null;
+                }
+            });
+        } catch (RemoteException e) {
+            Slog.w(TAG, "RemoteException in the audio service.");
+        }
+        mHasBluetoothRoute = (audioRoutes != null && audioRoutes.bluetoothName != null);
     }
 
     public void systemRunning() {
@@ -135,7 +186,7 @@
         final long token = Binder.clearCallingIdentity();
         try {
             synchronized (mLock) {
-                registerClientLocked(client, pid, packageName, resolvedUserId, trusted);
+                registerClientLocked(client, uid, pid, packageName, resolvedUserId, trusted);
             }
         } finally {
             Binder.restoreCallingIdentity(token);
@@ -178,6 +229,23 @@
 
     // Binder call
     @Override
+    public boolean isPlaybackActive(IMediaRouterClient client) {
+        if (client == null) {
+            throw new IllegalArgumentException("client must not be null");
+        }
+
+        final long token = Binder.clearCallingIdentity();
+        try {
+            synchronized (mLock) {
+                return isPlaybackActiveLocked(client);
+            }
+        } finally {
+            Binder.restoreCallingIdentity(token);
+        }
+    }
+
+    // Binder call
+    @Override
     public void setDiscoveryRequest(IMediaRouterClient client,
             int routeTypes, boolean activeScan) {
         if (client == null) {
@@ -276,6 +344,36 @@
         }
     }
 
+    void restoreBluetoothA2dp() {
+        try {
+            mAudioService.setBluetoothA2dpOn(mHasBluetoothRoute);
+        } catch (RemoteException e) {
+            Slog.w(TAG, "RemoteException while calling setBluetoothA2dpOn.");
+        }
+    }
+
+    void restoreRoute(int uid) {
+        ClientRecord clientRecord = null;
+        UserRecord userRecord = mUserRecords.get(UserHandle.getUserId(uid));
+        if (userRecord.mClientRecords != null) {
+            for (ClientRecord cr : userRecord.mClientRecords) {
+                if (validatePackageName(uid, cr.mPackageName)) {
+                    clientRecord = cr;
+                    break;
+                }
+            }
+        }
+        if (clientRecord != null) {
+            try {
+                clientRecord.mClient.onRestoreRoute();
+            } catch (RemoteException e) {
+                Slog.w(TAG, "Failed to call onRestoreRoute. Client probably died.");
+            }
+        } else {
+            restoreBluetoothA2dp();
+        }
+    }
+
     void switchUser() {
         synchronized (mLock) {
             int userId = ActivityManager.getCurrentUser();
@@ -304,7 +402,7 @@
     }
 
     private void registerClientLocked(IMediaRouterClient client,
-            int pid, String packageName, int userId, boolean trusted) {
+            int uid, int pid, String packageName, int userId, boolean trusted) {
         final IBinder binder = client.asBinder();
         ClientRecord clientRecord = mAllClientRecords.get(binder);
         if (clientRecord == null) {
@@ -314,7 +412,7 @@
                 userRecord = new UserRecord(userId);
                 newUser = true;
             }
-            clientRecord = new ClientRecord(userRecord, client, pid, packageName, trusted);
+            clientRecord = new ClientRecord(userRecord, client, uid, pid, packageName, trusted);
             try {
                 binder.linkToDeath(clientRecord, 0);
             } catch (RemoteException ex) {
@@ -350,6 +448,14 @@
         return null;
     }
 
+    private boolean isPlaybackActiveLocked(IMediaRouterClient client) {
+        ClientRecord clientRecord = mAllClientRecords.get(client.asBinder());
+        if (clientRecord != null) {
+            return mAudioPlaybackMonitor.isPlaybackActive(clientRecord.mUid);
+        }
+        return false;
+    }
+
     private void setDiscoveryRequestLocked(IMediaRouterClient client,
             int routeTypes, boolean activeScan) {
         final IBinder binder = client.asBinder();
@@ -489,6 +595,7 @@
     final class ClientRecord implements DeathRecipient {
         public final UserRecord mUserRecord;
         public final IMediaRouterClient mClient;
+        public final int mUid;
         public final int mPid;
         public final String mPackageName;
         public final boolean mTrusted;
@@ -498,9 +605,10 @@
         public String mSelectedRouteId;
 
         public ClientRecord(UserRecord userRecord, IMediaRouterClient client,
-                int pid, String packageName, boolean trusted) {
+                int uid, int pid, String packageName, boolean trusted) {
             mUserRecord = userRecord;
             mClient = client;
+            mUid = uid;
             mPid = pid;
             mPackageName = packageName;
             mTrusted = trusted;
@@ -997,7 +1105,7 @@
                     try {
                         mTempClients.get(i).onStateChanged();
                     } catch (RemoteException ex) {
-                        // ignore errors, client probably died
+                        Slog.w(TAG, "Failed to call onStateChanged. Client probably died.");
                     }
                 }
             } finally {
diff --git a/services/core/java/com/android/server/media/MediaSessionService.java b/services/core/java/com/android/server/media/MediaSessionService.java
index 38c6157..adb50f0 100644
--- a/services/core/java/com/android/server/media/MediaSessionService.java
+++ b/services/core/java/com/android/server/media/MediaSessionService.java
@@ -138,19 +138,20 @@
         mKeyguardManager =
                 (KeyguardManager) getContext().getSystemService(Context.KEYGUARD_SERVICE);
         mAudioService = getAudioService();
-        mAudioPlaybackMonitor = new AudioPlaybackMonitor(getContext(), mAudioService,
+        mAudioPlaybackMonitor = AudioPlaybackMonitor.getInstance(getContext(), mAudioService);
+        mAudioPlaybackMonitor.registerOnAudioPlaybackStartedListener(
                 new AudioPlaybackMonitor.OnAudioPlaybackStartedListener() {
-                    @Override
-                    public void onAudioPlaybackStarted(int uid) {
-                        synchronized (mLock) {
-                            FullUserRecord user =
-                                    getFullUserRecordLocked(UserHandle.getUserId(uid));
-                            if (user != null) {
-                                user.mPriorityStack.updateMediaButtonSessionIfNeeded();
-                            }
-                        }
+            @Override
+            public void onAudioPlaybackStarted(int uid) {
+                synchronized (mLock) {
+                    FullUserRecord user =
+                            getFullUserRecordLocked(UserHandle.getUserId(uid));
+                    if (user != null) {
+                        user.mPriorityStack.updateMediaButtonSessionIfNeeded();
                     }
-                });
+                }
+            }
+        });
         mAudioManagerInternal = LocalServices.getService(AudioManagerInternal.class);
         mContentResolver = getContext().getContentResolver();
         mSettingsObserver = new SettingsObserver();