Change repaintRectIncludingDescendants to repaintRectIncludingNonCompositingDescendants.

In other words, don't recurse into composited descendants. In all cases, the callers
 of repaintRectIncludingDescendants only want to update repaint rects for child layers that
paint into the same backing.

Review URL: https://codereview.chromium.org/319203003

git-svn-id: svn://svn.chromium.org/blink/trunk@175807 bbb929c8-8fbe-4397-9dbb-9b2b20218538