[chromium] Disable root layer clears on release builds.

[chromium] Disable root layer clears on release builds.
https://bugs.webkit.org/show_bug.cgi?id=77478

Patch by Jonathan Backer <backer@chromium.org> on 2012-02-08
Reviewed by James Robinson.

Source/WebCore:

* platform/graphics/chromium/LayerRendererChromium.cpp:
(WebCore::LayerRendererChromium::clearRenderSurface):
(WebCore::LayerRendererChromium::drawRenderPass):
* platform/graphics/chromium/LayerRendererChromium.h:
(LayerRendererChromium):

LayoutTests:

* platform/chromium-gpu-linux/fast/canvas/canvas-text-alignment-expected.png:
* platform/chromium-gpu-linux/media/video-zoom-expected.png:
* platform/chromium-linux/compositing/direct-image-compositing-expected.png:
* platform/chromium-linux/compositing/geometry/ancestor-overflow-change-expected.png:
* platform/chromium-linux/compositing/geometry/fixed-in-composited-expected.png:
* platform/chromium-linux/compositing/geometry/tall-page-composited-expected.png:
* platform/chromium-linux/compositing/masks/masked-ancestor-expected.png:
* platform/chromium-linux/compositing/masks/multiple-masks-expected.png:
* platform/chromium-linux/compositing/masks/simple-composited-mask-expected.png:
* platform/chromium-linux/compositing/scaling/tiled-layer-recursion-expected.png:
* platform/chromium-linux/platform/chromium/compositing/layout-width-change-expected.png:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@107120 268f45cc-cd09-0410-ab3c-d52691b4dbfc