Merge 102611 - [chromium] Remove assumption that empty surface is always at end of list

Merge 102611 - [chromium] Remove assumption that empty surface is always at end of list
https://bugs.webkit.org/show_bug.cgi?id=74037

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

Source/WebCore:

Test case added to CCLayerTreeHostCommonTest.cpp, which reproduces
a crash reported in http://code.google.com/p/chromium/issues/detail?id=106734

This patch fixes the crash in a less risky way to be merged into
m17, but the root of the issue needs to be addressed in a
follow-up patch.

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

Source/WebKit/chromium:

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

BUG=106734
TBR=jamesr@chromium.org