GitLab

Introduce a helper WebGLRenderingContextBase::GetContextTaskRunner()
and use it uniformly when posting tasks related to query objects, sync
objects, and timer query objects.

Tested with WebGL conformance tests being added in
https://github.com/KhronosGroup/WebGL/pull/3004 .

Bug: 1010877
Change-Id: I36128dca93fc7ff490abf503991b82992d9861d6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1999486Reviewed-by: James Darpinian <jdarpinian@chromium.org>
Commit-Queue: Kenneth Russell <kbr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#731795}