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In many situations the same GPU on different OEM devices manifest
different behaviors, so it's important to switch from 2-part
identification of a GPU (vendor_id, device_id) to 4-part:
  (vendor_id, device_id, sub_sys_id, revision)

This is the first CL. This adds the fields to GPUInfo and add
the info collection and wire the info to about:gpu page.

BUG=1006960
TEST=gpu_unittests, about:gpu
R=sunnyps@chromium.org,dcheng@chromium.org

Change-Id: Ia8623cdf842ec8eb899a018c26c9267fb9a2c880
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1824457
Commit-Queue: Zhenyao Mo <zmo@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Alexei Filippov <alph@chromium.org>
Reviewed-by: Sunny Sachanandani <sunnyps@chromium.org>
Cr-Commit-Position: refs/heads/master@{#700382}