Retain tray bubble's rounded corners when the bubble animates out
by transferring ownership of a layer mask to the associated layer.

BUG=235563
TEST=Manual: when closing an Ash tray menu or tray notification, watch corners
     to make sure they remain rounded.
R=piman@chromium.org, msw@chromium.org, mukai@chromium.org, skuhne@chromium.org

Review URL: https://codereview.chromium.org/25961002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239930 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 239930
Enable Instant Support - Part 1

This CL implements InstantSearchPrerenderer.

InstantSearchPrerenderer is responsible for prerendering default search provider Instant search base page URL to prefetch high-confidence search suggestion. It manages the prerender handle associated with the prerendered contents. When the user commits the search query, InstantSearchPrerenderer submits query to the prerendered page and the Browser will swap the prerendered contents with active web contents.

BUG=269186
TEST=none

Review URL: https://codereview.chromium.org/51813002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239931 0039d316-1c4b-4281-b951-d872f2087c98
Support GL_FLOAT and GL_HALF_FLOAT_OES as glReadPixels types when the gl context allows it.

BUG=314141

Review URL: https://codereview.chromium.org/89103002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239932 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 239932