Re-land: cc: Remove task references from RasterWorkerPool.

This moves the responsibility to keep tasks alive while scheduled
from the RasterWorkerPool to the client where unnecessary reference
counting can be avoided. The result is a ~5x improvement in
BuildRasterTaskQueue performance, which under some circumstances
translate to almost 2x improvement in ScheduleTasks performance.

BUG=269841
TEST=cc_perftests --gtest_filter=RasterWorkerPool*

Review URL: https://codereview.chromium.org/173953003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254436 0039d316-1c4b-4281-b951-d872f2087c98
Moved SuperFastHash function from base/hash.cc to base/third_party.

This code was written by Paul Hsieh under a 3-clause BSD license. It
belongs in third_party.

I did not move the existing implementation, but re-downloaded the code
from upstream:
http://www.azillionmonkeys.com/qed/hash.html
This version is formatted differently and is written in plain C, but it
is identical to the version that was previously in hash.cc.

Added LICENSE and README.chromium files, as well as adding license text
to the top of superfasthash.cc, as required by checklicenses.py.

BUG=347393

Review URL: https://codereview.chromium.org/181643004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254437 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 254436
Remove calls to WebRuntimeFeatures::enableStableFeatures

As of blink r166996[1], stable features are now enabled by default.

[1] https://src.chromium.org/viewvc/blink?view=rev&revision=166996

Review URL: https://codereview.chromium.org/166393003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254438 0039d316-1c4b-4281-b951-d872f2087c98
Rename InputMethodEngineIBusBrowserTest to InputMethodEngineBrowserTest.

R=nona@chromium.org
BUG=283612

Review URL: https://codereview.chromium.org/183973003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254439 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 254439
Automated Commit: Committing new LKGM version 5571.0.0 for chromeos.

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254440 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 254440