Source/WebCore: https://bugs.webkit.org/show_bug.cgi?id=68314

Source/WebCore: https://bugs.webkit.org/show_bug.cgi?id=68314

Make sure that the containing block loop when clipping to border-radius
terminates by checking if you hit the RenderView. Null checking isn't sufficient
for stupid historical reasons that should be fixed (i.e., the RenderView returns itself
as its own containing block, even though this should just be changed).

Reviewed by Simon Fraser and Darin Adler.

Added new test in fast/clip.

* rendering/RenderLayer.cpp:
(WebCore::inContainingBlockChain):

LayoutTests: https://bugs.webkit.org/show_bug.cgi?id=68314

Added some more clipping tests for overflow to make sure the right things happen
when border-radius is specified.

Reviewed by Simon Fraser and Darin Adler.

* fast/clip/overflow-border-radius-fixed-position.html: Added.
* platform/mac/fast/clip/overflow-border-radius-fixed-position-expected.png: Added.
* platform/mac/fast/clip/overflow-border-radius-fixed-position-expected.txt: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@95567 268f45cc-cd09-0410-ab3c-d52691b4dbfc