Switch transitions back to a "destination" model as far as choosing which transitions should apply on a style
        change.  Preserve the behavior of allowing stale transitions (in the absence of property changes) to run to
        completion.

        Reviewed by Dean

        * manual-tests/transitions.html:
        * manual-tests/transitions2.html:
        * page/AnimationController.cpp:
        (WebCore::ImplicitAnimation::reset):
        (WebCore::CompositeImplicitAnimation::animate):
        (WebCore::AnimationControllerPrivate::get):
        (WebCore::AnimationController::updateImplicitAnimations):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@35074 268f45cc-cd09-0410-ab3c-d52691b4dbfc