Allow WebGL on Android if the GPU has it's own process (Take 2)

First attempt ( was reverted due to
failures on the Android bots. This is because the Android bots use content shell,
not Chromium, to run the tests and that uses in-process GPU. As such the test
were running without WebGL support.

This patch adds back in the EXT_robusness exceptions, which allowed the bots to
run WebGL content previously and won't appear to users as a regression.


Review URL:

Cr-Commit-Position: refs/heads/master@{#340385}
10 files changed