Add the PrefixedMediaAddKey value back to the UseCounter enum.

It was removed in 150962, which changed the position of the following items
in the enum. That's a bad thing. This CL simply adds it back to restore the
expected positions of the enum's values.

BUG=224791
TBR=ddorwin@chromium.org,tkent@chromium.org

Review URL: https://codereview.chromium.org/15735019

git-svn-id: svn://svn.chromium.org/blink/trunk@150969 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix a crash when we try a focus navigation from a shadow host which is not keyboard navigatable, but focusable.

For example, suppose the following element:

  <div id=host tabindex=-1></div>
  host.webkitCreateShadowRoot()

This host element is focusable, but isn't keyboard navigatable.

We should relax the ASSERT condition so that this kind of element is okay as an old focused node.


BUG=241029

Review URL: https://chromiumcodereview.appspot.com/15728005

git-svn-id: svn://svn.chromium.org/blink/trunk@150970 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Preparation for code generation of InspectorInstrumentation: reordered methods, normalized whitespace

BUG=232160
TBR=vsevik

Review URL: https://chromiumcodereview.appspot.com/15737011

git-svn-id: svn://svn.chromium.org/blink/trunk@150971 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Update content shell test expectations

TBR=mkwst@chromium.org

Review URL: https://codereview.chromium.org/15834003

git-svn-id: svn://svn.chromium.org/blink/trunk@150972 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Moar test expectations for content shell mac

TBR=mkwst@chromium.org

Review URL: https://codereview.chromium.org/15844003

git-svn-id: svn://svn.chromium.org/blink/trunk@150973 bbb929c8-8fbe-4397-9dbb-9b2b20218538
ScriptInstance: Don't copy Persistent handles.

This gets rid of more places where Persistent handles are copied
(see bug).

BUG=236290

Review URL: https://chromiumcodereview.appspot.com/15742004

git-svn-id: svn://svn.chromium.org/blink/trunk@150974 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add image only failure text expectations for content shell win

TBR=mkwst@chromium.org
BUG=239769

Review URL: https://codereview.chromium.org/15850002

git-svn-id: svn://svn.chromium.org/blink/trunk@150975 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Clean up the transition tests.

Moves the transition test logic from transition-test-helpers to
animation-test-helpers. This allows us to run all animations/transitions
tests in a uniform way. Immediate benefit is that the transition tests
now use requestAnimationFrame rather than setTimeout when running in
real-time.

Several other cleanups
- Removed some tests that were redundant.
- Disabled pixel tests where we have coverage elsewhere.
- Updated expectations (since animation-test-helper produces simpler results)

BUG=235752

Review URL: https://chromiumcodereview.appspot.com/15738009

git-svn-id: svn://svn.chromium.org/blink/trunk@150976 bbb929c8-8fbe-4397-9dbb-9b2b20218538