Enable virtualized contexts on Linux AMD

A recent change to use SharedImage for WebGL has caused conformance
tests that copy from WebGL backbuffer to 2d canvas to fail on Linux
AMD bots which use native GL contexts.

It is speculated that this is due to flush ordering not working and
missing any other form of synchronization.  SharedImages are created on
the raster decoder context instead of the WebGL context which might be
just enough to change context scheduling and cause these issues.

Bug: 914976
Change-Id: I3c4fb1dfe4d5839a647dde5dc9ca047c6d630a7f
Reviewed-on: https://chromium-review.googlesource.com/c/1377729
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Commit-Queue: Sunny Sachanandani <sunnyps@chromium.org>
Cr-Commit-Position: refs/heads/master@{#616559}
1 file changed