Garden-O-Matic: Remove Function.prototype.bind polyfill which was for Safari 5

All modern browsers support Function.prototype.bind, certainly Chrome does!

R=arv@chromium.org,ojan@chromium.org

Review URL: https://chromiumcodereview.appspot.com/18800003

git-svn-id: svn://svn.chromium.org/blink/trunk@153647 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add support for accelerated fixed root background

Putting a fixed root background in a separate composited layer
requires a tiled layer cache currently. This patch makes it possible to
use the feature, even without a tiled layer cache.

This patch also adds fixes from this WebKit patch by Simon Fraser:
https://bugs.webkit.org/show_bug.cgi?id=115951

This patch depends on tests and plumbing provided by https://codereview.chromium.org/17398002/

BUG=180885

Review URL: https://chromiumcodereview.appspot.com/13462003

git-svn-id: svn://svn.chromium.org/blink/trunk@153648 bbb929c8-8fbe-4397-9dbb-9b2b20218538