[chromium] Scissor rect optimization for chromium compositor

[chromium] Scissor rect optimization for chromium compositor
https://bugs.webkit.org/show_bug.cgi?id=67341

Patch by Shawn Singh <shawnsingh@chromium.org> on 2011-12-02
Reviewed by James Robinson.

Mostly covered by damage tracker tests. Currently this relies on
manually running layout tests, because this patch requires partial
swaps that are not supported by DumpRenderTree. The feature
automatically disables if partial swap is not supported.

* platform/graphics/chromium/LayerRendererChromium.cpp:
(WebCore::LayerRendererChromium::initialize):
(WebCore::LayerRendererChromium::trackDamageForAllSurfaces):
(WebCore::LayerRendererChromium::drawLayersOntoRenderSurfaces):
(WebCore::LayerRendererChromium::drawLayersInternal):
(WebCore::LayerRendererChromium::swapBuffers):
(WebCore::LayerRendererChromium::drawLayer):
* platform/graphics/chromium/LayerRendererChromium.h:
* platform/graphics/chromium/cc/CCLayerTreeHost.h:
(WebCore::CCSettings::CCSettings):
(WebCore::LayerRendererCapabilities::LayerRendererCapabilities):
* platform/graphics/chromium/cc/CCRenderSurface.cpp:
(WebCore::CCRenderSurface::draw):
* platform/graphics/chromium/cc/CCRenderSurface.h:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@101908 268f45cc-cd09-0410-ab3c-d52691b4dbfc