Web Animations CSS: Set StyleChangeFromRenderer for all animation style changes

In r164013[1] the animation style change was moved from Animation to Element
but the StyleChangeFromRenderer signal was inadvertently suppressed when a
style recalc had already been requested.

[1] https://src.chromium.org/viewvc/blink?revision=164013&view=revision

BUG=332024

Review URL: https://codereview.chromium.org/130563011

git-svn-id: svn://svn.chromium.org/blink/trunk@167062 bbb929c8-8fbe-4397-9dbb-9b2b20218538