Delete chicken/egg compositing geometry updates

After this CL, we don't update the graphics layer geometry incrementally.
Instead, the updates are deferred until its actually time to do a compositing
update. There's a lot of cleanup we can do after this CL lands, but I wanted to
keep this CL small. We can do the cleanup in subsequent CLs.

Review URL: https://codereview.chromium.org/218993017

git-svn-id: svn://svn.chromium.org/blink/trunk@170630 bbb929c8-8fbe-4397-9dbb-9b2b20218538