emugl: Introduce BufferQueue class.

This patch introduces a new class that will be used in a future
patch that refactors the RenderChannel interface and its
implementation.

BufferQueue implements a FIFO queue of RenderChannel::Buffer
instances, where each instance is protected from thread races
by an external mutex. This allows the caller to use several
instances at the same time without introducing hard
synchronization issues (e.g. thread races).

+ Add a new unit-test program, lib[64]OpenglRender_unittest
  that is run by android-rebuild.sh by default.

Change-Id: I39adf4aa4a19990b5138c9b2294c063d3bae4a78
5 files changed