To fix the green title edge problem (Native)

The problem was caused by alpha blending between some useless
green lines in the title image and the input image. In the
patch, we correct this wrong title boundary and only perform
blending between input image and title area.
There is also a very great side effect that: the computation
complexity is significantly reduced. It saves the exporting
time up to 60% for 1080P video with title effect.

Change-Id: Ic7bb763271e2c0edd21d834ad2c0b4e9dbdcecf0
Author: Wei Feng <wei.feng@intel.com>
Signed-off-by: Wei Feng <wei.feng@intel.com>
Signed-off-by: Shuo Gao <shuo.gao@intel.com>
Signed-off-by: Bruce Beare <bruce.j.beare@intel.com>
Signed-off-by: Jack Ren <jack.ren@intel.com>
Author-tracking-BZ: 39058
audio: Use composition instead of multiple inheritance

- AudioTrack is derived from BnDirectTrackClient along
  with RefBase to receive the notifications from
  AudioFlinger in tunnel/LPA mode. This is breaking
  binary compatibility for the clients which use native
  AudioTrack directly instead of Java based AudioTrack
  API
- Fix is to use composition here instead of inheritance

Change-Id: I9fd2c61cff5629924e3b08f63559679e0263bcfd

Conflicts:
	include/media/AudioTrack.h