Merge 117645 - [chromium] add back-face visibility check for renderSurfaces

Merge 117645 - [chromium] add back-face visibility check for renderSurfaces
https://bugs.webkit.org/show_bug.cgi?id=86870

Reviewed by Adrienne Walker.

Source/WebCore:

Test added CCLayerTreeHostCommonTest::verifyBackFaceCullingWithPreserves3dForFlatteningSurface

Chromium was not checking back-face visibility for renderSurfaces
that needed it. This patch adds that check and the appropriate
unit test.

* platform/graphics/chromium/cc/CCLayerTreeHostCommon.cpp:
(WebCore::layerIsInExisting3DRenderingContext):
(WebCore):
(WebCore::subtreeShouldRenderToSeparateSurface):
(WebCore::calculateDrawTransformsAndVisibilityInternal):

Source/WebKit/chromium:

* tests/CCLayerTreeHostCommonTest.cpp:
(WebKitTests::TEST):
(WebKitTests):

TBR=shawnsingh@chromium.org
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=118119