Don't force rendering in finishAllRendering

Don't force rendering in finishAllRendering
https://bugs.webkit.org/show_bug.cgi?id=86919

Reviewed by James Robinson.

After we acquire the texture layers on the main thread, we can't draw.
In particular if we destroyed the texture ids used previously by
TextureLayerChromium, drawing before a commit would cause a
bind-after-destroy.

Tested by CCLayerTreeHostTestFinishAllRendering.

* platform/graphics/chromium/cc/CCThreadProxy.cpp:
(WebCore::CCThreadProxy::CCThreadProxy):
(WebCore::CCThreadProxy::finishAllRenderingOnImplThread):
(WebCore::CCThreadProxy::scheduledActionDrawAndSwapInternal):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@117825 268f45cc-cd09-0410-ab3c-d52691b4dbfc