It's reasonable to use the serial logic on both the GL and all other
translated Renderers, since we check the logic on the GL-side.
Serials give us a way to identify Textures that aren't raw pointers
and aren't "id". "id" has issues when Textures are deleted, then
re-allocated with the same value.

BUG=angle:781

Change-Id: I1a2a8b6f4ea3db915574c957c143a81e0210ec7d
Reviewed-on: https://chromium-review.googlesource.com/222922Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Brandon Jones <bajones@chromium.org>