Fix bug 5300223 Lockscreen should recycle bitmaps

When receiving a new bitmap to display, the lockscreen should
 recycle the old bitmap (if any).

Change-Id: Ic4f65a797dfe7e3cae7a0559f6333cc99e2ae1e7

Author: jmtrivi

core/java/com/android/internal/widget/TransportControlView.java

@@ -102,6 +102,9 @@ public void handleMessage(Message msg) {
 
             case MSG_SET_ARTWORK:
                 if (mClientGeneration == msg.arg1) {
+                    if (mMetadata.bitmap != null) {
+                        mMetadata.bitmap.recycle();
+                    }
                     mMetadata.bitmap = (Bitmap) msg.obj;
                     mAlbumArt.setImageBitmap(mMetadata.bitmap);
                 }