GLES2Debugger: Make command exchange async to improve performance.

In message loop, use select to check for available commands from client,
 rather than always expecting commands in eglSwapBuffers.

Change-Id: Ifc34dd77c2528c8b9c71f594e3eda4f93400cd2b
Signed-off-by: David Li <davidxli@google.com>
10 files changed