Delete GLRenderer and related classes

This CL deletes GLRenderer and related classes that were used solely by
it like GLOutputSurface, GLRendererCopier, etc. It also removes the
kUseSkiaRenderer feature and some similar flags since it's no longer
possible to turn off SkiaRenderer.

This deletes the GLRenderer code itself. There is a follow up CL to
delete another large chunk of related GL command buffer code that's no
longer needed. After that there will be a long tail of cleanup CLs that
are broader reaching.

Bug: 1247756
Change-Id: Id99562921ec4da09f27240f1cf07ba51427368f4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3652749
Reviewed-by: Brian Ho <hob@chromium.org>
Reviewed-by: danakj <danakj@chromium.org>
Commit-Queue: Kyle Charbonneau <kylechar@chromium.org>
Reviewed-by: Bo Liu <boliu@chromium.org>
Reviewed-by: Peng Huang <penghuang@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1009746}