MediaPlayerService: fix access of mPlayer in client am: 502c2f4053 am: bd7db202c6 am: 03fa67202f am: 263d5a2a70 am: 0844e1a3e8 am: e0f4963584 am: 5cc9f8780c am: 93ae13644b am: 50280c1b44 am: 1a1bb632e7 am: d8192c9149 am: 6f7295a384 am: 830ecba34d am: ee04f896ca am: b65bc512d1
am: 6b79fa9965

Change-Id: I05c6510ddd4abd449e3bf75ec3d8ae8fdaa45917