Web Animations CSS: Unfreeze AnimationClock if sampling timelines does not trigger style recalc

When sampling the animations and transitions timelines, we set the
AnimationClock's time and freeze it so that subsequent accesses of the clock's
time during style recalc receive the same value. The clock is unfrozen when
style recalc completes.

However, if a timeline is sampled after its last Player is removed, it will not
trigger style recalc *. This can occur if a transition is cancelled
prematurely. In this case, we will fail to unfreeze the clock, so transitions
started subsequently will see a stale clock time.

This change modifies DocumentTimeline::serviceAnimations() to unfreeze the
AnimationClock if it did not trigger a style recalc. It also adds a test to
verify this behavior.

* In non-CSS uses of the Web Animations model, a timeline can also fail to
trigger style recalc if its animations have no effect or no target.

BUG=303430,248938
R=timloh@chromium.org

Review URL: https://codereview.chromium.org/46043014

git-svn-id: svn://svn.chromium.org/blink/trunk@161134 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Notify WebSocket connection failure, Blink side

In order to set |wasClean| property of CloseEvent and show the failure message
correctly, The blink-side WebSocket need to know whether the connection
is dropped because of a server request.

chromium side change is: https://codereview.chromium.org/34753008/

BUG=310405

Review URL: https://codereview.chromium.org/36033003

git-svn-id: svn://svn.chromium.org/blink/trunk@161135 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Update license header in generated files

Per:
http://www.chromium.org/blink/coding-style#TOC-License

Review URL: https://codereview.chromium.org/54673008

git-svn-id: svn://svn.chromium.org/blink/trunk@161136 bbb929c8-8fbe-4397-9dbb-9b2b20218538