Merge 98392 - LayerRendererChromium::setVisible called needlessly without a visibility change

Merge 98392 - LayerRendererChromium::setVisible called needlessly without a visibility change
https://bugs.webkit.org/show_bug.cgi?id=70766

Patch by Michal Mocny <mmocny@google.com>; on 2011-10-25
Reviewed by Kenneth Russell.

Check that visibility has actually changed before calling LayerRendererChromium::setVisible

* platform/graphics/chromium/cc/CCLayerTreeHostImpl.cpp:
(WebCore::CCLayerTreeHostImpl::CCLayerTreeHostImpl):
(WebCore::CCLayerTreeHostImpl::setVisible):
* platform/graphics/chromium/cc/CCLayerTreeHostImpl.h:

TBR=commit-queue@webkit.org
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=99504