Re-land: content: Single process support for native GpuMemoryBuffers.
This adds single process support for IOSurface and
SurfaceTexture backed GpuMemoryBuffers.
Also makes the SurfaceTexture code more consistent
with IOSurface code by using a singleton instead of
leaking a raw pointer.
BUG=497559
TEST=content_browsertests --gtest_also_run_disabled_tests --gtest_filter=ChildThreadImplGpuMemoryBufferBrowserTests/*
Review URL: https://codereview.chromium.org/
1120873002
Cr-Commit-Position: refs/heads/master@{#333822}