GitLab

Remove another instance of ContextGL from the shared main thread
context in preparation for OOPR Canvas. Also a semi-step toward
supporting texture upload on RasterInterface. Since
RasterImplementationGLES just wraps glTexSubImage2D I anticipate that
the WritePixels interface will look different for the
RasterImplementation version as it won't rely on texture_target.

Bug: 1063725, 1018898
Change-Id: I5ae922b5496690e4b6135e98fa0bcb76c144d7f9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2119635Reviewed-by: Khushal <khushalsagar@chromium.org>
Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Nathan Zabriskie <nazabris@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#753408}