MediaSync: rename bufferIndex to bufferId.
MediaSync: rename bufferIndex to bufferId.

Bug: 20887706
Change-Id: I98887832bc2211614a19a3718b46d6da100f6c9b

xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base