Testing the GL/ CPU encoding w/ Gralloc buffers

This is the test for Gralloc buffers based encoding.
contains a combination of two main changes:

1. GL based encoding tests added to SurfaceMediaSource_test

2. SurfaceMediaSource ::read() colorformat

The SurfaceMediaSource::getformat() sets it to OMX_COLOR_FormatAndroidOpaque.
The omx encoder needs to interpret that colorformat and reads the format
from the Gralloc buffers directly

Change-Id: Iee2fe8901384109a4952e1d6c528c59eb01eb5b1