ericrk@, were you able to look at this?

Took a look, actually seems really easy to add - CL out.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5c34fe289869ccd38b3cf39add76b00e2c51cb97

commit 5c34fe289869ccd38b3cf39add76b00e2c51cb97
Author: ericrk <ericrk@chromium.org>
Date: Thu Jan 19 18:53:10 2017

Add SHA1 data checksum to on-disk shader cache

Previously, the on-disk cache was stored with a SHA1 hash of a number
of common peices of system info, such as GL Vendor, OS version, etc...

This change adds the actual data being stored to the SHA1, which should
protect against corruption on disk.

BUG= 658779 

Review-Url: https://codereview.chromium.org/2638933003
Cr-Commit-Position: refs/heads/master@{#444802}

[modify] https://crrev.com/5c34fe289869ccd38b3cf39add76b00e2c51cb97/content/browser/gpu/gpu_process_host.cc
[modify] https://crrev.com/5c34fe289869ccd38b3cf39add76b00e2c51cb97/content/browser/gpu/gpu_process_host.h
[modify] https://crrev.com/5c34fe289869ccd38b3cf39add76b00e2c51cb97/tools/metrics/histograms/histograms.xml

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/06d94217594da5c82a4f5c67d90fd2d81cf613fa

commit 06d94217594da5c82a4f5c67d90fd2d81cf613fa
Author: Eric Karl <ericrk@chromium.org>
Date: Mon Aug 07 23:33:52 2017

Disable hash validation in shader disk cache

The sha1 hash leads to problems with double-caching of shaders.
The binary representation of a shader (protobuf) is not stable, as
protobuf fields are rearranged in subsequent usages of the shader.

While these rearranged protobufs have no meaningful differences,
they lead to new hashes, causing the shader to be double cached.

As the hash validation had no impact on the crash-on-upgrade issue it
was intended to fix, it's probably easiest to just remove it.

Bug:  658779 
Change-Id: Ic470e16e4ae6a0b66fd8d8f2c0aa3207455588fe
Reviewed-on: https://chromium-review.googlesource.com/604333
Commit-Queue: Eric Karl <ericrk@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#492447}
[modify] https://crrev.com/06d94217594da5c82a4f5c67d90fd2d81cf613fa/content/browser/gpu/gpu_process_host.cc
[modify] https://crrev.com/06d94217594da5c82a4f5c67d90fd2d81cf613fa/content/browser/gpu/gpu_process_host.h