Replace CSSAnimationData::Create(CSSAnimation) with clone method.

To copy a CSSAnimationData, we use CSSAnimationData::Create(o).
However, this interface is inconsistent with many other classes that
instead provide a clone method to do the same thing. This patch replaces
the Create method with a Clone method to be consistent.

BUG=628043

Review-Url: https://codereview.chromium.org/2886893007
Cr-Commit-Position: refs/heads/master@{#473049}
2 files changed