Fix assert failure in RenderObjectChildList::removeChildNode

Inserting an element before the fullscreened element could crash if it
caused a containing inline to be split, since the splitting logic
doesn't expect the fullscreened element to be wrapped in a
RenderFullScreen. This commit changes inline splitting to be aware of
RenderFullScreen. 

BUG=177688

Review URL: https://chromiumcodereview.appspot.com/15165002

git-svn-id: svn://svn.chromium.org/blink/trunk@150447 bbb929c8-8fbe-4397-9dbb-9b2b20218538
3 files changed