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The command buffer perftests run multiple tests in different
configurations. To get the full matrix, we run the full set of
tests with the two main configurations: the 'validating' and
'passthrough' command buffer. This avoids having to spin up the
process multiple times in the same set of tests, and iterate over
the same set of tests.

Also update the owners for GPU related tests to include a group
for all perf alerts related to Chrome GPU tests, and add components
to relevant tests.

Builds on http://crrev.com/c/743683.

BUG=angleproject:2188

Change-Id: I418eb1dc4e3fd355f413790fac59a37d329b9dff
Reviewed-on: https://chromium-review.googlesource.com/733617
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Ned Nguyen <nednguyen@google.com>
Reviewed-by: Simon Hatch <simonhatch@chromium.org>
Cr-Commit-Position: refs/heads/master@{#512720}