D3D9: Use angle::Format when possible. This will unify the way we call into PackPixels and also cleans u the code. It required adding a few D3D9-specific formats to the table. BUG=angleproject:1455 Change-Id: Ic8282f40f52cabdb2925e2bb305c26582284082d Reviewed-on: https://chromium-review.googlesource.com/365825 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Zhenyao Mo <zmo@chromium.org>