Roll libvpx: cc9c0c:8dc6ea

Roll libvpx: cc9c0c:8dc6ea

Turn on AVX2 optimizations
https://codereview.chromium.org/863143002

Add them to GN build file:
https://codereview.chromium.org/865893004

Correct CPU detection:
https://codereview.chromium.org//864393002

Win GN build flag:
https://codereview.chromium.org//817293008

R=tomfinegan@chromium.org

Committed: https://crrev.com/efd856c2a46810e742f7aba0130d534783db6b2a
Cr-Commit-Position: refs/heads/master@{#312712}

[Johann, 2015-01-22 20:54:10]

Red builds look unrelated. Some of the tests didn't appear to start correctly,
or it failed to compile with and without the patch, or there is an error in
accessibility which appears to be a flake.

[Tom Finegan, 2015-01-22 20:56:29]

On 2015/01/22 20:54:10, Johann wrote:
> Red builds look unrelated. Some of the tests didn't appear to start correctly,
> or it failed to compile with and without the patch, or there is an error in
> accessibility which appears to be a flake.

Let's see what the cq things... lgtm

[Johann, 2015-01-22 21:39:52]

The CQ bit was checked by johannkoenig@google.com

[commit-bot: I haz the power, 2015-01-22 21:41:24]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/845453005/40001

[commit-bot: I haz the power, 2015-01-23 00:26:32]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-01-23 00:27:51]

Patchset 3 (id:??) landed as
https://crrev.com/efd856c2a46810e742f7aba0130d534783db6b2a
Cr-Commit-Position: refs/heads/master@{#312712}

[Nico, 2015-01-23 02:14:33]

thakis@chromium.org changed reviewers:
+ thakis@chromium.org

[Nico, 2015-01-23 02:14:34]

fyi, the avx2 stuff caused
https://code.google.com/p/chromium/issues/detail?id=451290

Is avx2 active on any chips we care about?

[Michael Achenbach, 2015-01-23 10:55:39]

FYI: V8 also broke the vista/xp bots with an AVX change yesterday (unrelated to
this).
Failing builds:
http://build.chromium.org/p/chromium.win/builders/Vista%20Tests%20%281%29/bui...
Root cause:
https://codereview.chromium.org/860003002
Next try that keeps it off on old win systems:
https://codereview.chromium.org/869133002

[binjin, 2015-01-23 11:14:26]

A revert of this CL (patchset #3 id:40001) has been created in
https://codereview.chromium.org/869973003/ by binjin@chromium.org.

The reason for reverting is: Suspected to cause multiple tests failure on win
vista bot

http://build.chromium.org/p/chromium.win/builders/Vista%20Tests%20%281%29?num...
http://build.chromium.org/p/chromium.win/builders/Vista%20Tests%20%281%29/bui....