Part of project Ribbon

This refactor is one step in the process of refactoring out property
specific logic inside switch cases in
CSSPropertyParser::ParseSingleValue. This is required to implement the
parseSingleValue methods in the property APIs without passing property
ID to the API.

Given that the IsValidAnimationPropertyList function only ever returned
false if the property passed was CSSPropertyTransitionProperty, this
check was moved to the calling methods.

The next step in this process will be to refactor out the need to pass
property to the ConsumeAnimationPropertyList function. At this stage the
call to IsValidAnimationPropertyList will be moved to the
CSSPropertyTransitionProperty case only and the check for this property
will be removed.

The check for this property in
CSSPropertyParser::ConsumeAnimationShorthand will be refactored out at a
later stage in project Ribbon.

BUG=668012

Review-Url: https://codereview.chromium.org/2835893002
Cr-Commit-Position: refs/heads/master@{#467277}