Introduce new method commitRegion to TextureD3D. Replacing commitRect with commitRegion, which takes generic parameter types, will allow us to call it directly from the base class TextureD3D. This will be useful in subsequent patches that introduce the SubData performance workaround. BUG=angle:729 Change-Id: I37bf12f847b43f7c961b403321de19f547258b01 Reviewed-on: https://chromium-review.googlesource.com/220274 Tested-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org>