Gallery: fix a memory leak

If video playing is completed, not paused or cancelled, the Runnables
posted are not removed from the Handler. Make sure they are removed.

Change-Id: I4c27583e4305398b35188c494b6da15f809439b9
CRs-Fixed: 999702
diff --git a/src/com/android/gallery3d/app/MoviePlayer.java b/src/com/android/gallery3d/app/MoviePlayer.java
index 720c504..47c9b12 100644
--- a/src/com/android/gallery3d/app/MoviePlayer.java
+++ b/src/com/android/gallery3d/app/MoviePlayer.java
@@ -694,12 +694,14 @@
         }
         if (mMovieItem.getError()) {
             Log.w(TAG, "error occured, exit the video player!");
+            mHandler.removeCallbacksAndMessages(null);
             mActivityContext.finish();
             return;
         }
         if (mPlayerExt.getLoop()) {
             onReplay();
         } else { //original logic
+            mHandler.removeCallbacksAndMessages(null);
             mTState = TState.COMPELTED;
             if (mCanReplay) {
                 mController.showEnded();