Skip eglSwapBuffers() call when we do not draw to GL

The fix is to track when we issue GL drawing commands, and to skip the
call to eglSwapBuffers() when a DisplayList does not result in
any actual rendering calls to GL.

Issue #6364143 QuickMuni list items and buttons flicker instead of fade

Change-Id: I60a02c61a58c32d92481a1e814b4c8a49c6a37a3
7 files changed