Correctly handle control labels inside canvas fallback content.

The code changes are trivial, just moving code from
AccessibilityRenderObject to AccessibilityNodeObject,
with trivial changes to make the code work there.

Elements inside canvas fallback content are not rendered
but are otherwise accessible; eventually we should move as
much logic as possible to AccessibilityNodeObject so that
there are few differences between inside of a canvas and
outside for accessibility.

BUG=none

Review URL: https://chromiumcodereview.appspot.com/22797007

git-svn-id: svn://svn.chromium.org/blink/trunk@156767 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Web Animations: Fix elpasedTime in animation events

This addresses the FIXME in CSSAnimations::EventDelegate::onEventCondition()
to pass the TimedItem to the event callback.

Also tighten up a test such that it would now detect the FIXME.

BUG=240653
R=dstockwell

Review URL: https://chromiumcodereview.appspot.com/23039013

git-svn-id: svn://svn.chromium.org/blink/trunk@156768 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Make <dialog> ARIA-aware.

With this patch:
1. Inert nodes behave like 'aria-disabled' is true.
2. <dialog> has a default role of 'dialog'

As according to the spec:
http://www.whatwg.org/specs/web-apps/current-work/multipage/elements.html#wai-aria

BUG=264959

Review URL: https://chromiumcodereview.appspot.com/22903038

git-svn-id: svn://svn.chromium.org/blink/trunk@156769 bbb929c8-8fbe-4397-9dbb-9b2b20218538