Increase the minimum GPU memory limit on Mac

Increase the minimum GPU memory limit for a renderer from 64MB to
128MB. The Mac's memory policy will not actually use the full amount of
memory, unless the page requires that much to render content on the
screen (in which case, jank due to paging is better than missing
content).

Make the prioritized resource manager more aggressively free unused
textures when the memory policy indicates that GPU memory should be
used sparingly. Without this change, the amount of memory spent holding
on to spare textures to recycle would double.

Move the definition of the priority cutoff to the same location as
all other platform dependent variables.

BUG=318877

Review URL: https://codereview.chromium.org/98073011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241769 0039d316-1c4b-4281-b951-d872f2087c98
Revert 241737 "Disable NaClBrowserTest.PPAPIPPPInstance."

[Reverting because it's superceded by r241743, a more fine grained fix]

> Disable NaClBrowserTest.PPAPIPPPInstance.
> 
> This has been failing flakily in its NaClBrowserTestPnacl.PPAPIPPPInstance
> incarnation, and in others as well according to the description
> on the bug. The earliest instance of a failure I saw on the
> flakiness dashboard was 12/13/2013 7:41:03 AM. That dashboard
> is here: http://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=browser_tests&tests=NaClBrowserTestPnacl.PPAPIPPPInstance
> 
> TBR=ncbray@chromium.org
> BUG=329511
> 
> Review URL: https://codereview.chromium.org/117393005

TBR=nick@chromium.org

Review URL: https://codereview.chromium.org/118503005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241770 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 241770
Revert 241755 "Use libyuv::ConvertToI420 for all all color forma..."

[Reason for revert: failed compile on android AOSP builder: http://build.chromium.org/p/chromium.linux/builders/Android%20Webview%20AOSP%20Builder/builds/7101 ]

> Use libyuv::ConvertToI420 for all all color formats in video capture on WIN
> 
> Since libyuv has added support for image flipping (vertically) with negative
> src_height as indicator, we'd converge all color formats into one code path.
> And libyuv provides better performance.
> 
> BUG=
> R=sergeyu@chromium.org
> 
> Review URL: https://codereview.chromium.org/116573005

TBR=wjia@chromium.org

Review URL: https://codereview.chromium.org/104393003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241771 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 241771