diff --git a/api/current.txt b/api/current.txt
index 658478be435c2..abc9e9a2b1636 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -22553,6 +22553,10 @@ package android.media.session {
     method public void playFromMediaId(java.lang.String, android.os.Bundle);
     method public void playFromSearch(java.lang.String, android.os.Bundle);
     method public void playFromUri(android.net.Uri, android.os.Bundle);
+    method public void prepare();
+    method public void prepareFromMediaId(java.lang.String, android.os.Bundle);
+    method public void prepareFromSearch(java.lang.String, android.os.Bundle);
+    method public void prepareFromUri(android.net.Uri, android.os.Bundle);
     method public void rewind();
     method public void seekTo(long);
     method public void sendCustomAction(android.media.session.PlaybackState.CustomAction, android.os.Bundle);
@@ -22586,7 +22590,6 @@ package android.media.session {
     method public void setRatingType(int);
     method public void setSessionActivity(android.app.PendingIntent);
     field public static final int FLAG_HANDLES_MEDIA_BUTTONS = 1; // 0x1
-    field public static final int FLAG_HANDLES_PREPARE_ONLY = 4; // 0x4
     field public static final int FLAG_HANDLES_TRANSPORT_CONTROLS = 2; // 0x2
   }
 
@@ -22601,6 +22604,10 @@ package android.media.session {
     method public void onPlayFromMediaId(java.lang.String, android.os.Bundle);
     method public void onPlayFromSearch(java.lang.String, android.os.Bundle);
     method public void onPlayFromUri(android.net.Uri, android.os.Bundle);
+    method public void onPrepare();
+    method public void onPrepareFromMediaId(java.lang.String, android.os.Bundle);
+    method public void onPrepareFromSearch(java.lang.String, android.os.Bundle);
+    method public void onPrepareFromUri(android.net.Uri, android.os.Bundle);
     method public void onRewind();
     method public void onSeekTo(long);
     method public void onSetRating(android.media.Rating);
@@ -22657,6 +22664,10 @@ package android.media.session {
     field public static final long ACTION_PLAY_FROM_SEARCH = 2048L; // 0x800L
     field public static final long ACTION_PLAY_FROM_URI = 8192L; // 0x2000L
     field public static final long ACTION_PLAY_PAUSE = 512L; // 0x200L
+    field public static final long ACTION_PREPARE = 16384L; // 0x4000L
+    field public static final long ACTION_PREPARE_FROM_MEDIA_ID = 32768L; // 0x8000L
+    field public static final long ACTION_PREPARE_FROM_SEARCH = 65536L; // 0x10000L
+    field public static final long ACTION_PREPARE_FROM_URI = 131072L; // 0x20000L
     field public static final long ACTION_REWIND = 8L; // 0x8L
     field public static final long ACTION_SEEK_TO = 256L; // 0x100L
     field public static final long ACTION_SET_RATING = 128L; // 0x80L
@@ -22665,7 +22676,6 @@ package android.media.session {
     field public static final long ACTION_SKIP_TO_QUEUE_ITEM = 4096L; // 0x1000L
     field public static final long ACTION_STOP = 1L; // 0x1L
     field public static final android.os.Parcelable.Creator<android.media.session.PlaybackState> CREATOR;
-    field public static final java.lang.String EXTRA_PREPARE_ONLY = "android.media.session.extra.PREPARE_ONLY";
     field public static final long PLAYBACK_POSITION_UNKNOWN = -1L; // 0xffffffffffffffffL
     field public static final int STATE_BUFFERING = 6; // 0x6
     field public static final int STATE_CONNECTING = 8; // 0x8
diff --git a/api/system-current.txt b/api/system-current.txt
index 6646c28b43be4..b36d7e89cb8d1 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -24126,6 +24126,10 @@ package android.media.session {
     method public void playFromMediaId(java.lang.String, android.os.Bundle);
     method public void playFromSearch(java.lang.String, android.os.Bundle);
     method public void playFromUri(android.net.Uri, android.os.Bundle);
+    method public void prepare();
+    method public void prepareFromMediaId(java.lang.String, android.os.Bundle);
+    method public void prepareFromSearch(java.lang.String, android.os.Bundle);
+    method public void prepareFromUri(android.net.Uri, android.os.Bundle);
     method public void rewind();
     method public void seekTo(long);
     method public void sendCustomAction(android.media.session.PlaybackState.CustomAction, android.os.Bundle);
@@ -24159,7 +24163,6 @@ package android.media.session {
     method public void setRatingType(int);
     method public void setSessionActivity(android.app.PendingIntent);
     field public static final int FLAG_HANDLES_MEDIA_BUTTONS = 1; // 0x1
-    field public static final int FLAG_HANDLES_PREPARE_ONLY = 4; // 0x4
     field public static final int FLAG_HANDLES_TRANSPORT_CONTROLS = 2; // 0x2
   }
 
@@ -24174,6 +24177,10 @@ package android.media.session {
     method public void onPlayFromMediaId(java.lang.String, android.os.Bundle);
     method public void onPlayFromSearch(java.lang.String, android.os.Bundle);
     method public void onPlayFromUri(android.net.Uri, android.os.Bundle);
+    method public void onPrepare();
+    method public void onPrepareFromMediaId(java.lang.String, android.os.Bundle);
+    method public void onPrepareFromSearch(java.lang.String, android.os.Bundle);
+    method public void onPrepareFromUri(android.net.Uri, android.os.Bundle);
     method public void onRewind();
     method public void onSeekTo(long);
     method public void onSetRating(android.media.Rating);
@@ -24230,6 +24237,10 @@ package android.media.session {
     field public static final long ACTION_PLAY_FROM_SEARCH = 2048L; // 0x800L
     field public static final long ACTION_PLAY_FROM_URI = 8192L; // 0x2000L
     field public static final long ACTION_PLAY_PAUSE = 512L; // 0x200L
+    field public static final long ACTION_PREPARE = 16384L; // 0x4000L
+    field public static final long ACTION_PREPARE_FROM_MEDIA_ID = 32768L; // 0x8000L
+    field public static final long ACTION_PREPARE_FROM_SEARCH = 65536L; // 0x10000L
+    field public static final long ACTION_PREPARE_FROM_URI = 131072L; // 0x20000L
     field public static final long ACTION_REWIND = 8L; // 0x8L
     field public static final long ACTION_SEEK_TO = 256L; // 0x100L
     field public static final long ACTION_SET_RATING = 128L; // 0x80L
@@ -24238,7 +24249,6 @@ package android.media.session {
     field public static final long ACTION_SKIP_TO_QUEUE_ITEM = 4096L; // 0x1000L
     field public static final long ACTION_STOP = 1L; // 0x1L
     field public static final android.os.Parcelable.Creator<android.media.session.PlaybackState> CREATOR;
-    field public static final java.lang.String EXTRA_PREPARE_ONLY = "android.media.session.extra.PREPARE_ONLY";
     field public static final long PLAYBACK_POSITION_UNKNOWN = -1L; // 0xffffffffffffffffL
     field public static final int STATE_BUFFERING = 6; // 0x6
     field public static final int STATE_CONNECTING = 8; // 0x8
diff --git a/api/test-current.txt b/api/test-current.txt
index f1908c150b428..3878fbf25e315 100644
--- a/api/test-current.txt
+++ b/api/test-current.txt
@@ -22562,6 +22562,10 @@ package android.media.session {
     method public void playFromMediaId(java.lang.String, android.os.Bundle);
     method public void playFromSearch(java.lang.String, android.os.Bundle);
     method public void playFromUri(android.net.Uri, android.os.Bundle);
+    method public void prepare();
+    method public void prepareFromMediaId(java.lang.String, android.os.Bundle);
+    method public void prepareFromSearch(java.lang.String, android.os.Bundle);
+    method public void prepareFromUri(android.net.Uri, android.os.Bundle);
     method public void rewind();
     method public void seekTo(long);
     method public void sendCustomAction(android.media.session.PlaybackState.CustomAction, android.os.Bundle);
@@ -22595,7 +22599,6 @@ package android.media.session {
     method public void setRatingType(int);
     method public void setSessionActivity(android.app.PendingIntent);
     field public static final int FLAG_HANDLES_MEDIA_BUTTONS = 1; // 0x1
-    field public static final int FLAG_HANDLES_PREPARE_ONLY = 4; // 0x4
     field public static final int FLAG_HANDLES_TRANSPORT_CONTROLS = 2; // 0x2
   }
 
@@ -22610,6 +22613,10 @@ package android.media.session {
     method public void onPlayFromMediaId(java.lang.String, android.os.Bundle);
     method public void onPlayFromSearch(java.lang.String, android.os.Bundle);
     method public void onPlayFromUri(android.net.Uri, android.os.Bundle);
+    method public void onPrepare();
+    method public void onPrepareFromMediaId(java.lang.String, android.os.Bundle);
+    method public void onPrepareFromSearch(java.lang.String, android.os.Bundle);
+    method public void onPrepareFromUri(android.net.Uri, android.os.Bundle);
     method public void onRewind();
     method public void onSeekTo(long);
     method public void onSetRating(android.media.Rating);
@@ -22666,6 +22673,10 @@ package android.media.session {
     field public static final long ACTION_PLAY_FROM_SEARCH = 2048L; // 0x800L
     field public static final long ACTION_PLAY_FROM_URI = 8192L; // 0x2000L
     field public static final long ACTION_PLAY_PAUSE = 512L; // 0x200L
+    field public static final long ACTION_PREPARE = 16384L; // 0x4000L
+    field public static final long ACTION_PREPARE_FROM_MEDIA_ID = 32768L; // 0x8000L
+    field public static final long ACTION_PREPARE_FROM_SEARCH = 65536L; // 0x10000L
+    field public static final long ACTION_PREPARE_FROM_URI = 131072L; // 0x20000L
     field public static final long ACTION_REWIND = 8L; // 0x8L
     field public static final long ACTION_SEEK_TO = 256L; // 0x100L
     field public static final long ACTION_SET_RATING = 128L; // 0x80L
@@ -22674,7 +22685,6 @@ package android.media.session {
     field public static final long ACTION_SKIP_TO_QUEUE_ITEM = 4096L; // 0x1000L
     field public static final long ACTION_STOP = 1L; // 0x1L
     field public static final android.os.Parcelable.Creator<android.media.session.PlaybackState> CREATOR;
-    field public static final java.lang.String EXTRA_PREPARE_ONLY = "android.media.session.extra.PREPARE_ONLY";
     field public static final long PLAYBACK_POSITION_UNKNOWN = -1L; // 0xffffffffffffffffL
     field public static final int STATE_BUFFERING = 6; // 0x6
     field public static final int STATE_CONNECTING = 8; // 0x8
diff --git a/media/java/android/media/session/ISessionCallback.aidl b/media/java/android/media/session/ISessionCallback.aidl
index adb6b0600f972..893bd3c8cbb13 100644
--- a/media/java/android/media/session/ISessionCallback.aidl
+++ b/media/java/android/media/session/ISessionCallback.aidl
@@ -29,6 +29,10 @@ oneway interface ISessionCallback {
     void onMediaButton(in Intent mediaButtonIntent, int sequenceNumber, in ResultReceiver cb);
 
     // These callbacks are for the TransportPerformer
+    void onPrepare();
+    void onPrepareFromMediaId(String mediaId, in Bundle extras);
+    void onPrepareFromSearch(String query, in Bundle extras);
+    void onPrepareFromUri(in Uri uri, in Bundle extras);
     void onPlay();
     void onPlayFromMediaId(String mediaId, in Bundle extras);
     void onPlayFromSearch(String query, in Bundle extras);
diff --git a/media/java/android/media/session/ISessionController.aidl b/media/java/android/media/session/ISessionController.aidl
index 285e5f7a0880a..249bcdc802cea 100644
--- a/media/java/android/media/session/ISessionController.aidl
+++ b/media/java/android/media/session/ISessionController.aidl
@@ -50,6 +50,10 @@ interface ISessionController {
     void setVolumeTo(int value, int flags, String packageName);
 
     // These commands are for the TransportControls
+    void prepare();
+    void prepareFromMediaId(String mediaId, in Bundle extras);
+    void prepareFromSearch(String string, in Bundle extras);
+    void prepareFromUri(in Uri uri, in Bundle extras);
     void play();
     void playFromMediaId(String mediaId, in Bundle extras);
     void playFromSearch(String string, in Bundle extras);
diff --git a/media/java/android/media/session/MediaController.java b/media/java/android/media/session/MediaController.java
index 3d9b60deed2f6..13db00ef3cd1c 100644
--- a/media/java/android/media/session/MediaController.java
+++ b/media/java/android/media/session/MediaController.java
@@ -591,6 +591,90 @@ public final class MediaController {
         private TransportControls() {
         }
 
+        /**
+         * Request that the player prepare its playback. Once the preparation is done, the session
+         * will change its playback state to {@link PlaybackState#STATE_PAUSED}. Afterwards,
+         * {@link #play} can be called to start playback. If the preparation is not needed,
+         * {@link #play} can be directly called without this method.
+         */
+        public void prepare() {
+            try {
+                mSessionBinder.prepare();
+            } catch (RemoteException e) {
+                Log.wtf(TAG, "Error calling prepare.", e);
+            }
+        }
+
+        /**
+         * Request that the player prepare playback for a specific media id. Once the preparation is
+         * done, the session will change its playback state to {@link PlaybackState#STATE_PAUSED}.
+         * Afterwards, {@link #play} can be called to start playback. If the preparation is not
+         * needed, {@link #playFromMediaId} can be directly called without this method.
+         *
+         * @param mediaId The id of the requested media.
+         * @param extras Optional extras that can include extra information about the media item
+         *               to be prepared.
+         */
+        public void prepareFromMediaId(String mediaId, Bundle extras) {
+            if (TextUtils.isEmpty(mediaId)) {
+                throw new IllegalArgumentException(
+                        "You must specify a non-empty String for prepareFromMediaId.");
+            }
+            try {
+                mSessionBinder.prepareFromMediaId(mediaId, extras);
+            } catch (RemoteException e) {
+                Log.wtf(TAG, "Error calling prepare(" + mediaId + ").", e);
+            }
+        }
+
+        /**
+         * Request that the player prepare playback for a specific search query.
+         * An empty or null query should be treated as a request to prepare any
+         * music. Once the preparation is done, the session will change its playback state to
+         * {@link PlaybackState#STATE_PAUSED}. Afterwards, {@link #play} can be called to start
+         * playback. If the preparation is not needed, {@link #playFromSearch} can be directly
+         * called without this method.
+         *
+         * @param query The search query.
+         * @param extras Optional extras that can include extra information
+         *               about the query.
+         */
+        public void prepareFromSearch(String query, Bundle extras) {
+            if (query == null) {
+                // This is to remain compatible with
+                // INTENT_ACTION_MEDIA_PLAY_FROM_SEARCH
+                query = "";
+            }
+            try {
+                mSessionBinder.prepareFromSearch(query, extras);
+            } catch (RemoteException e) {
+                Log.wtf(TAG, "Error calling prepare(" + query + ").", e);
+            }
+        }
+
+        /**
+         * Request that the player prepare playback for a specific {@link Uri}.
+         * Once the preparation is done, the session will change its playback state to
+         * {@link PlaybackState#STATE_PAUSED}. Afterwards, {@link #play} can be called to start
+         * playback. If the preparation is not needed, {@link #playFromUri} can be directly
+         * called without this method.
+         *
+         * @param uri The URI of the requested media.
+         * @param extras Optional extras that can include extra information about the media item
+         *               to be prepared.
+         */
+        public void prepareFromUri(Uri uri, Bundle extras) {
+            if (uri == null || Uri.EMPTY.equals(uri)) {
+                throw new IllegalArgumentException(
+                        "You must specify a non-empty Uri for prepareFromUri.");
+            }
+            try {
+                mSessionBinder.prepareFromUri(uri, extras);
+            } catch (RemoteException e) {
+                Log.wtf(TAG, "Error calling prepare(" + uri + ").", e);
+            }
+        }
+
         /**
          * Request that the player start its playback at its current position.
          */
@@ -605,7 +689,6 @@ public final class MediaController {
         /**
          * Request that the player start playback for a specific media id.
          *
-         * @see PlaybackState#EXTRA_PREPARE_ONLY
          * @param mediaId The id of the requested media.
          * @param extras Optional extras that can include extra information about the media item
          *               to be played.
@@ -627,10 +710,9 @@ public final class MediaController {
          * An empty or null query should be treated as a request to play any
          * music.
          *
-         * @see PlaybackState#EXTRA_PREPARE_ONLY
          * @param query The search query.
          * @param extras Optional extras that can include extra information
-         *            about the query.
+         *               about the query.
          */
         public void playFromSearch(String query, Bundle extras) {
             if (query == null) {
@@ -648,8 +730,7 @@ public final class MediaController {
         /**
          * Request that the player start playback for a specific {@link Uri}.
          *
-         * @see PlaybackState#EXTRA_PREPARE_ONLY
-         * @param uri  The URI of the requested media.
+         * @param uri The URI of the requested media.
          * @param extras Optional extras that can include extra information about the media item
          *               to be played.
          */
diff --git a/media/java/android/media/session/MediaSession.java b/media/java/android/media/session/MediaSession.java
index 8c5b19c36f116..3b1b6c86ffcb0 100644
--- a/media/java/android/media/session/MediaSession.java
+++ b/media/java/android/media/session/MediaSession.java
@@ -86,12 +86,6 @@ public final class MediaSession {
      */
     public static final int FLAG_HANDLES_TRANSPORT_CONTROLS = 1 << 1;
 
-    /**
-     * Set this flag on the session to indicate that it can handle
-     * the {@link PlaybackState#EXTRA_PREPARE_ONLY} field.
-     */
-    public static final int FLAG_HANDLES_PREPARE_ONLY = 1 << 2;
-
     /**
      * System only flag for a session that needs to have priority over all other
      * sessions. This flag ensures this session will receive media button events
@@ -106,7 +100,6 @@ public final class MediaSession {
     @IntDef(flag = true, value = {
             FLAG_HANDLES_MEDIA_BUTTONS,
             FLAG_HANDLES_TRANSPORT_CONTROLS,
-            FLAG_HANDLES_PREPARE_ONLY,
             FLAG_EXCLUSIVE_GLOBAL_PRIORITY })
     public @interface SessionFlags { }
 
@@ -519,6 +512,22 @@ public final class MediaSession {
         }
     }
 
+    private void dispatchPrepare() {
+        postToCallback(CallbackMessageHandler.MSG_PREPARE);
+    }
+
+    private void dispatchPrepareFromMediaId(String mediaId, Bundle extras) {
+        postToCallback(CallbackMessageHandler.MSG_PREPARE_MEDIA_ID, mediaId, extras);
+    }
+
+    private void dispatchPrepareFromSearch(String query, Bundle extras) {
+        postToCallback(CallbackMessageHandler.MSG_PREPARE_SEARCH, query, extras);
+    }
+
+    private void dispatchPrepareFromUri(Uri uri, Bundle extras) {
+        postToCallback(CallbackMessageHandler.MSG_PREPARE_URI, uri, extras);
+    }
+
     private void dispatchPlay() {
         postToCallback(CallbackMessageHandler.MSG_PLAY);
     }
@@ -805,16 +814,49 @@ public final class MediaSession {
         }
 
         /**
-         * Override to handle requests to begin playback.
+         * Override to handle requests to prepare playback. The state of playback should be updated
+         * to {@link PlaybackState#STATE_PAUSED} after the preparation is done. Override
+         * {@link #onPlay} to handle requests for starting playback of prepared content.
          */
-        public void onPlay() {
+        public void onPrepare() {
         }
 
         /**
-         * Override to handle requests to play a specific mediaId that was
-         * provided by your app's {@link MediaBrowserService}.
+         * Override to handle requests to prepare for playing a specific mediaId that was provided
+         * by your app's {@link MediaBrowserService}. The state of playback should be updated
+         * to {@link PlaybackState#STATE_PAUSED} after the preparation is done. The playback of
+         * the prepared content should start in the implementation of {@link #onPlay}. Override
+         * {@link #onPlayFromMediaId} to handle requests for starting playback without preparation.
          */
-        public void onPlayFromMediaId(String mediaId, Bundle extras) {
+        public void onPrepareFromMediaId(String mediaId, Bundle extras) {
+        }
+
+        /**
+         * Override to handle requests to prepare playback from a search query. An
+         * empty query indicates that the app may prepare any music. The
+         * implementation should attempt to make a smart choice about what to
+         * play. The state of playback should be updated to {@link PlaybackState#STATE_PAUSED}
+         * after the preparation is done. The playback of the prepared content should start
+         * in the implementation of {@link #onPlay}. Override {@link #onPlayFromSearch}
+         * to handle requests for starting playback without preparation.
+         */
+        public void onPrepareFromSearch(String query, Bundle extras) {
+        }
+
+        /**
+         * Override to handle requests to prepare a specific media item represented by a URI.
+         * The state of playback should be updated to {@link PlaybackState#STATE_PAUSED}
+         * after the preparation is done. The playback of the prepared content should start in
+         * the implementation of {@link #onPlay}. Override {@link #onPlayFromUri} to handle requests
+         * for starting playback without preparation.
+         */
+        public void onPrepareFromUri(Uri uri, Bundle extras) {
+        }
+
+        /**
+         * Override to handle requests to begin playback.
+         */
+        public void onPlay() {
         }
 
         /**
@@ -826,6 +868,13 @@ public final class MediaSession {
         public void onPlayFromSearch(String query, Bundle extras) {
         }
 
+        /**
+         * Override to handle requests to play a specific mediaId that was
+         * provided by your app's {@link MediaBrowserService}.
+         */
+        public void onPlayFromMediaId(String mediaId, Bundle extras) {
+        }
+
         /**
          * Override to handle requests to play a specific media item represented by a URI.
          */
@@ -936,6 +985,38 @@ public final class MediaSession {
             }
         }
 
+        @Override
+        public void onPrepare() {
+            MediaSession session = mMediaSession.get();
+            if (session != null) {
+                session.dispatchPrepare();
+            }
+        }
+
+        @Override
+        public void onPrepareFromMediaId(String mediaId, Bundle extras) {
+            MediaSession session = mMediaSession.get();
+            if (session != null) {
+                session.dispatchPrepareFromMediaId(mediaId, extras);
+            }
+        }
+
+        @Override
+        public void onPrepareFromSearch(String query, Bundle extras) {
+            MediaSession session = mMediaSession.get();
+            if (session != null) {
+                session.dispatchPrepareFromSearch(query, extras);
+            }
+        }
+
+        @Override
+        public void onPrepareFromUri(Uri uri, Bundle extras) {
+            MediaSession session = mMediaSession.get();
+            if (session != null) {
+                session.dispatchPrepareFromUri(uri, extras);
+            }
+        }
+
         @Override
         public void onPlay() {
             MediaSession session = mMediaSession.get();
@@ -1162,24 +1243,28 @@ public final class MediaSession {
 
     private class CallbackMessageHandler extends Handler {
 
-        private static final int MSG_PLAY = 1;
-        private static final int MSG_PLAY_MEDIA_ID = 2;
-        private static final int MSG_PLAY_SEARCH = 3;
-        private static final int MSG_SKIP_TO_ITEM = 4;
-        private static final int MSG_PAUSE = 5;
-        private static final int MSG_STOP = 6;
-        private static final int MSG_NEXT = 7;
-        private static final int MSG_PREVIOUS = 8;
-        private static final int MSG_FAST_FORWARD = 9;
-        private static final int MSG_REWIND = 10;
-        private static final int MSG_SEEK_TO = 11;
-        private static final int MSG_RATE = 12;
-        private static final int MSG_CUSTOM_ACTION = 13;
-        private static final int MSG_MEDIA_BUTTON = 14;
-        private static final int MSG_COMMAND = 15;
-        private static final int MSG_ADJUST_VOLUME = 16;
-        private static final int MSG_SET_VOLUME = 17;
-        private static final int MSG_PLAY_URI = 18;
+        private static final int MSG_COMMAND = 1;
+        private static final int MSG_MEDIA_BUTTON = 2;
+        private static final int MSG_PREPARE = 3;
+        private static final int MSG_PREPARE_MEDIA_ID = 4;
+        private static final int MSG_PREPARE_SEARCH = 5;
+        private static final int MSG_PREPARE_URI = 6;
+        private static final int MSG_PLAY = 7;
+        private static final int MSG_PLAY_MEDIA_ID = 8;
+        private static final int MSG_PLAY_SEARCH = 9;
+        private static final int MSG_PLAY_URI = 10;
+        private static final int MSG_SKIP_TO_ITEM = 11;
+        private static final int MSG_PAUSE = 12;
+        private static final int MSG_STOP = 13;
+        private static final int MSG_NEXT = 14;
+        private static final int MSG_PREVIOUS = 15;
+        private static final int MSG_FAST_FORWARD = 16;
+        private static final int MSG_REWIND = 17;
+        private static final int MSG_SEEK_TO = 18;
+        private static final int MSG_RATE = 19;
+        private static final int MSG_CUSTOM_ACTION = 20;
+        private static final int MSG_ADJUST_VOLUME = 21;
+        private static final int MSG_SET_VOLUME = 22;
 
         private MediaSession.Callback mCallback;
 
@@ -1210,6 +1295,25 @@ public final class MediaSession {
         public void handleMessage(Message msg) {
             VolumeProvider vp;
             switch (msg.what) {
+                case MSG_COMMAND:
+                    Command cmd = (Command) msg.obj;
+                    mCallback.onCommand(cmd.command, cmd.extras, cmd.stub);
+                    break;
+                case MSG_MEDIA_BUTTON:
+                    mCallback.onMediaButtonEvent((Intent) msg.obj);
+                    break;
+                case MSG_PREPARE:
+                    mCallback.onPrepare();
+                    break;
+                case MSG_PREPARE_MEDIA_ID:
+                    mCallback.onPrepareFromMediaId((String) msg.obj, msg.getData());
+                    break;
+                case MSG_PREPARE_SEARCH:
+                    mCallback.onPrepareFromSearch((String) msg.obj, msg.getData());
+                    break;
+                case MSG_PREPARE_URI:
+                    mCallback.onPrepareFromUri((Uri) msg.obj, msg.getData());
+                    break;
                 case MSG_PLAY:
                     mCallback.onPlay();
                     break;
@@ -1252,13 +1356,6 @@ public final class MediaSession {
                 case MSG_CUSTOM_ACTION:
                     mCallback.onCustomAction((String) msg.obj, msg.getData());
                     break;
-                case MSG_MEDIA_BUTTON:
-                    mCallback.onMediaButtonEvent((Intent) msg.obj);
-                    break;
-                case MSG_COMMAND:
-                    Command cmd = (Command) msg.obj;
-                    mCallback.onCommand(cmd.command, cmd.extras, cmd.stub);
-                    break;
                 case MSG_ADJUST_VOLUME:
                     synchronized (mLock) {
                         vp = mVolumeProvider;
diff --git a/media/java/android/media/session/PlaybackState.java b/media/java/android/media/session/PlaybackState.java
index 1079a1f9a1077..1485cd782605a 100644
--- a/media/java/android/media/session/PlaybackState.java
+++ b/media/java/android/media/session/PlaybackState.java
@@ -133,19 +133,32 @@ public final class PlaybackState implements Parcelable {
     public static final long ACTION_PLAY_FROM_URI = 1 << 13;
 
     /**
-     * Used as an optional boolean extra field in
-     * {@link MediaController.TransportControls#playFromMediaId},
-     * {@link MediaController.TransportControls#playFromSearch}, and
-     * {@link MediaController.TransportControls#playFromUri}. Value of {@code true} overrides
-     * the default behavior of starting the playback after preparing. Check
-     * {@link MediaSession#FLAG_HANDLES_PREPARE_ONLY} to see if the media session supports this.
+     * Indicates this session supports the prepare command.
      *
-     * @see MediaSession#FLAG_HANDLES_PREPARE_ONLY
-     * @see MediaController.TransportControls#playFromMediaId
-     * @see MediaController.TransportControls#playFromSearch
-     * @see MediaController.TransportControls#playFromUri
+     * @see Builder#setActions(long)
      */
-    public static final String EXTRA_PREPARE_ONLY = "android.media.session.extra.PREPARE_ONLY";
+    public static final long ACTION_PREPARE = 1 << 14;
+
+    /**
+     * Indicates this session supports the prepare from media id command.
+     *
+     * @see Builder#setActions(long)
+     */
+    public static final long ACTION_PREPARE_FROM_MEDIA_ID = 1 << 15;
+
+    /**
+     * Indicates this session supports the prepare from search command.
+     *
+     * @see Builder#setActions(long)
+     */
+    public static final long ACTION_PREPARE_FROM_SEARCH = 1 << 16;
+
+    /**
+     * Indicates this session supports the prepare from URI command.
+     *
+     * @see Builder#setActions(long)
+     */
+    public static final long ACTION_PREPARE_FROM_URI = 1 << 17;
 
     /**
      * This is the default playback state and indicates that no media has been
@@ -330,6 +343,10 @@ public final class PlaybackState implements Parcelable {
      * <li> {@link PlaybackState#STATE_REWINDING}</li>
      * <li> {@link PlaybackState#STATE_BUFFERING}</li>
      * <li> {@link PlaybackState#STATE_ERROR}</li>
+     * <li> {@link PlaybackState#STATE_CONNECTING}</li>
+     * <li> {@link PlaybackState#STATE_SKIPPING_TO_PREVIOUS}</li>
+     * <li> {@link PlaybackState#STATE_SKIPPING_TO_NEXT}</li>
+     * <li> {@link PlaybackState#STATE_SKIPPING_TO_QUEUE_ITEM}</li>
      * </ul>
      */
     public int getState() {
@@ -380,6 +397,10 @@ public final class PlaybackState implements Parcelable {
      * <li> {@link PlaybackState#ACTION_PLAY_FROM_SEARCH}</li>
      * <li> {@link PlaybackState#ACTION_SKIP_TO_QUEUE_ITEM}</li>
      * <li> {@link PlaybackState#ACTION_PLAY_FROM_URI}</li>
+     * <li> {@link PlaybackState#ACTION_PREPARE}</li>
+     * <li> {@link PlaybackState#ACTION_PREPARE_FROM_MEDIA_ID}</li>
+     * <li> {@link PlaybackState#ACTION_PREPARE_FROM_SEARCH}</li>
+     * <li> {@link PlaybackState#ACTION_PREPARE_FROM_URI}</li>
      * </ul>
      */
     public long getActions() {
@@ -831,6 +852,10 @@ public final class PlaybackState implements Parcelable {
          * <li> {@link PlaybackState#STATE_REWINDING}</li>
          * <li> {@link PlaybackState#STATE_BUFFERING}</li>
          * <li> {@link PlaybackState#STATE_ERROR}</li>
+         * <li> {@link PlaybackState#STATE_CONNECTING}</li>
+         * <li> {@link PlaybackState#STATE_SKIPPING_TO_PREVIOUS}</li>
+         * <li> {@link PlaybackState#STATE_SKIPPING_TO_NEXT}</li>
+         * <li> {@link PlaybackState#STATE_SKIPPING_TO_QUEUE_ITEM}</li>
          * </ul>
          *
          * @param state The current state of playback.
@@ -870,6 +895,10 @@ public final class PlaybackState implements Parcelable {
          * <li> {@link PlaybackState#STATE_REWINDING}</li>
          * <li> {@link PlaybackState#STATE_BUFFERING}</li>
          * <li> {@link PlaybackState#STATE_ERROR}</li>
+         * <li> {@link PlaybackState#STATE_CONNECTING}</li>
+         * <li> {@link PlaybackState#STATE_SKIPPING_TO_PREVIOUS}</li>
+         * <li> {@link PlaybackState#STATE_SKIPPING_TO_NEXT}</li>
+         * <li> {@link PlaybackState#STATE_SKIPPING_TO_QUEUE_ITEM}</li>
          * </ul>
          *
          * @param state The current state of playback.
@@ -900,6 +929,10 @@ public final class PlaybackState implements Parcelable {
          * <li> {@link PlaybackState#ACTION_PLAY_FROM_SEARCH}</li>
          * <li> {@link PlaybackState#ACTION_SKIP_TO_QUEUE_ITEM}</li>
          * <li> {@link PlaybackState#ACTION_PLAY_FROM_URI}</li>
+         * <li> {@link PlaybackState#ACTION_PREPARE}</li>
+         * <li> {@link PlaybackState#ACTION_PREPARE_FROM_MEDIA_ID}</li>
+         * <li> {@link PlaybackState#ACTION_PREPARE_FROM_SEARCH}</li>
+         * <li> {@link PlaybackState#ACTION_PREPARE_FROM_URI}</li>
          * </ul>
          *
          * @param actions The set of actions allowed.
diff --git a/services/core/java/com/android/server/media/MediaSessionRecord.java b/services/core/java/com/android/server/media/MediaSessionRecord.java
index 246da2e10de52..862c061c6b9c5 100644
--- a/services/core/java/com/android/server/media/MediaSessionRecord.java
+++ b/services/core/java/com/android/server/media/MediaSessionRecord.java
@@ -868,6 +868,38 @@ public class MediaSessionRecord implements IBinder.DeathRecipient {
             }
         }
 
+        public void prepare() {
+            try {
+                mCb.onPrepare();
+            } catch (RemoteException e) {
+                Slog.e(TAG, "Remote failure in prepare.", e);
+            }
+        }
+
+        public void prepareFromMediaId(String mediaId, Bundle extras) {
+            try {
+                mCb.onPrepareFromMediaId(mediaId, extras);
+            } catch (RemoteException e) {
+                Slog.e(TAG, "Remote failure in prepareFromMediaId.", e);
+            }
+        }
+
+        public void prepareFromSearch(String query, Bundle extras) {
+            try {
+                mCb.onPrepareFromSearch(query, extras);
+            } catch (RemoteException e) {
+                Slog.e(TAG, "Remote failure in prepareFromSearch.", e);
+            }
+        }
+
+        public void prepareFromUri(Uri uri, Bundle extras) {
+            try {
+                mCb.onPrepareFromUri(uri, extras);
+            } catch (RemoteException e) {
+                Slog.e(TAG, "Remote failure in prepareFromUri.", e);
+            }
+        }
+
         public void play() {
             try {
                 mCb.onPlay();
@@ -880,7 +912,7 @@ public class MediaSessionRecord implements IBinder.DeathRecipient {
             try {
                 mCb.onPlayFromMediaId(mediaId, extras);
             } catch (RemoteException e) {
-                Slog.e(TAG, "Remote failure in playUri.", e);
+                Slog.e(TAG, "Remote failure in playFromMediaId.", e);
             }
         }
 
@@ -1099,6 +1131,27 @@ public class MediaSessionRecord implements IBinder.DeathRecipient {
             }
         }
 
+        @Override
+        public void prepare() throws RemoteException {
+            mSessionCb.prepare();
+        }
+
+        @Override
+        public void prepareFromMediaId(String mediaId, Bundle extras)
+                throws RemoteException {
+            mSessionCb.prepareFromMediaId(mediaId, extras);
+        }
+
+        @Override
+        public void prepareFromSearch(String query, Bundle extras) throws RemoteException {
+            mSessionCb.prepareFromSearch(query, extras);
+        }
+
+        @Override
+        public void prepareFromUri(Uri uri, Bundle extras) throws RemoteException {
+            mSessionCb.prepareFromUri(uri, extras);
+        }
+
         @Override
         public void play() throws RemoteException {
             mSessionCb.play();