The MSDN documentation states that BGRA4, RGB5A1 and RGB565 should all
support 4 samples with DXGI 1.2 and D3D11.1 but some drivers appear to
not have full support.  Fall back to RGBA8 render targets when the
driver cannot support at least 4 samples for ES3 feature levels.

BUG=761489

Change-Id: I6bcd417700f1188945e8032ca6a64c4fbb2bc8a8
Reviewed-on: https://chromium-review.googlesource.com/652828Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>