Auto-rebaseline for r183777

http://src.chromium.org/viewvc/blink?view=revision&revision=183777

BUG=422050
TBR=noel@chromium.org

Review URL: https://codereview.chromium.org/644323004

git-svn-id: svn://svn.chromium.org/blink/trunk@183779 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Web Animations: Overhaul and trace play state in AnimationPlayer

Adds an update scope and instruments call sites which require an up-to-date
current time or modify the play state. Tracing now displays spans for the pending
and running phases.

BUG=351446

Review URL: https://codereview.chromium.org/638313002

git-svn-id: svn://svn.chromium.org/blink/trunk@183780 bbb929c8-8fbe-4397-9dbb-9b2b20218538