[chromium] Only initiate the beginFrameAndCommit sequence if a commit has been requested

[chromium] Only initiate the beginFrameAndCommit sequence if a commit has been requested
https://bugs.webkit.org/show_bug.cgi?id=68967

Patch by James Robinson <jamesr@chromium.org> on 2011-09-27
Reviewed by Kenneth Russell.

When updating the scheduler state, we should only initiate a new commit flow if a commit has been requested (as
opposed to only a redraw).

Covered by the unit test CCLayerTreeHostTestSetNeedsRedraw with USE(THREADED_COMPOSITING) set to true.

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

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@96185 268f45cc-cd09-0410-ab3c-d52691b4dbfc