Add a failing Mac Lion test expectation per bug 108291.

* platform/mac/TestExpectations:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@141220 268f45cc-cd09-0410-ab3c-d52691b4dbfc
Rubberband scrolling on news.google.com causes text to blink repeatedly
https://bugs.webkit.org/show_bug.cgi?id=107326

Reviewed by Beth Dakin.

When in the middle of layout, RenderBlock::updateScrollInfoAfterLayout()
could cause us to re-evaluate reasons for compositing, via the call
to updateLayerCompositingState() in RenderLayer::updateScrollInfoAfterLayout().

At this time, when layout is still happening, it's bad to look at render
geometry to decide when to do compositing (e.g. for fixed position); we might
incorrectly conclude that the layer is outside the viewport.

Fix by having RenderLayerCompositing store in a member whether it's safe
to look at layout information. requiresCompositingForPosition() then consults
this bit, and, if it needs to make decisions based on layout but layout is not
complete, it doesn't change the compositing state of the layer.

Not testable, since dumping the layer tree will update layout and mask the bug.

* rendering/RenderLayerCompositor.cpp:
(WebCore::RenderLayerCompositor::RenderLayerCompositor):
(WebCore::RenderLayerCompositor::updateCompositingLayers):
(WebCore::RenderLayerCompositor::requiresCompositingForPosition):
* rendering/RenderLayerCompositor.h:
(RenderLayerCompositor):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@141221 268f45cc-cd09-0410-ab3c-d52691b4dbfc