Web Animations CSS: implement transform and filter support for scheduling
animations on the compositor.

BUG=298211

Review URL: https://codereview.chromium.org/72263002

git-svn-id: svn://svn.chromium.org/blink/trunk@162072 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Do not dispatch 'beforeload' event inside FrameView::layout().

Executing JavaScript code inside FrameView::layout() is problematic.
e.g. an assertion failure tested in fast/events/beforeload-assertion.html.
We should avoid it.

This CL  makes 'beforeload' event dispatching for plugins and iframes asynchronous,
except plugin access from JavaScript code (HTMLPlugInElement::
renderWidgetForJSBindings).

BUG=265889,313005,315979
R=esprehn@chromium.org

Review URL: https://codereview.chromium.org/61763016

git-svn-id: svn://svn.chromium.org/blink/trunk@162073 bbb929c8-8fbe-4397-9dbb-9b2b20218538