Fix crash caused by unrooted selection-start

Don't call containerForPaintInvalidation() from RenderSelectionInfo
if the object is not rooted.

BUG=414406

Review URL: https://codereview.chromium.org/572743002

git-svn-id: svn://svn.chromium.org/blink/trunk@182030 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Web Animations: Fix pseudo element keyframe style resolution crash

Pseudo element keyframe animations were not being resolved with the correct
StyleResolverState::element(). This bug is likely due to mismatched
parameter names in CSSAnimations::calculateUpdate().

This patch corrects the Element passed to StyleResolverState when resolving
keyframe animation styles and ensures the parameter names under
CSSAnimations::calculateUpdate() and related helper functions are consistent
with what gets passed in from StyleResolver::applyAnimatedProperties().

BUG=412979, 360457

Review URL: https://codereview.chromium.org/566803002

git-svn-id: svn://svn.chromium.org/blink/trunk@182031 bbb929c8-8fbe-4397-9dbb-9b2b20218538