Add first unit-test for TextIterator.

A new unit test is added in order to help us understand TextIterator's behavior
better. There is only one simple test for now.

BUG=none
R=yosin@chromium.org,morrita@chromium.org

Review URL: https://codereview.chromium.org/60983007

git-svn-id: svn://svn.chromium.org/blink/trunk@161705 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Move Web Animations methods out of StyleResolver.

Move the methods styleForKeyframe, matchScopedKeyframesRule,
GenerateTimingFunction, and resolveKeyframes out of StyleResolver
and into CSSAnimations. Expose methods and types in StyleResolver
as needed by the transplanted methods.

Change is made in preparation for adding use-counter analytics to
Web Animations, to avoid adding more WA-specific code to the Style
Resolver.

BUG=

Review URL: https://codereview.chromium.org/57593002

git-svn-id: svn://svn.chromium.org/blink/trunk@161706 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix accelerated animations that are reversed and use a bezier timing function

R=mithro

Review URL: https://codereview.chromium.org/32983005

git-svn-id: svn://svn.chromium.org/blink/trunk@161707 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Make ExecutionContext not own refcount.

This change delegate refcount entity from
ExecutionContext to ExecutionContextClient.

This is a preparation for Document-ExecutionContext decoupling.
We don't want ExecutionContext to outlive its owner.
This change reflects that direction.

R=abarth@chromium.org, abarth, dglazkov, haraken
BUG=305497

Review URL: https://codereview.chromium.org/61733008

git-svn-id: svn://svn.chromium.org/blink/trunk@161709 bbb929c8-8fbe-4397-9dbb-9b2b20218538