[Texmap] Synchronize layers only if the layer has been changed.
https://bugs.webkit.org/show_bug.cgi?id=112095

Patch by No'am Rosenthal <noam@webkit.org> on 2013-03-14
Reviewed by Allan Sandfeld Jensen.

A regression was introduced in r144787, causing an infinite IPC commitState/renderNextFrame
loop.
This patch fixes this by making sure we only commit layer states that have actual pending
changes.

No new tests, this is an optimization.

* platform/graphics/texmap/coordinated/CoordinatedGraphicsLayer.cpp:
(WebCore::CoordinatedGraphicsLayer::flushCompositingStateForThisLayerOnly):
* platform/graphics/texmap/coordinated/CoordinatedGraphicsState.h:
(CoordinatedGraphicsLayerState):
(WebCore::CoordinatedGraphicsLayerState::hasPendingChanges):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@145806 268f45cc-cd09-0410-ab3c-d52691b4dbfc