Remove non-overlap testing code in RenderLayerCompositor
https://bugs.webkit.org/show_bug.cgi?id=85521

Reviewed by Simon Fraser.

m_compositingConsultsOverlap is always true in the current
code. This patch removes this flag, and removes dead code that is
never executed because it was never false.

No new tests, no change in behavior.  The cleanup is covered by
existing tests.

* rendering/RenderLayer.cpp:
(WebCore::RenderLayer::updateCompositingLayersAfterScroll):
removed if-statement that is always true.

* rendering/RenderLayerBacking.cpp:
(WebCore::RenderLayerBacking::shouldClipCompositedBounds):
removed if-statement that would never get triggered.

* rendering/RenderLayerCompositor.cpp:
(WebCore::RenderLayerCompositor::RenderLayerCompositor):
(WebCore::RenderLayerCompositor::updateCompositingLayers):
removed m_compositingConsultsOverlap, and retained the code as if the flag were "true".

* rendering/RenderLayerCompositor.h:
(RenderLayerCompositor):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@148765 268f45cc-cd09-0410-ab3c-d52691b4dbfc
Make StringImpl::cost const
https://bugs.webkit.org/show_bug.cgi?id=114790

Reviewed by Andreas Kling.

* wtf/text/StringImpl.h:
(WTF::StringImpl::cost):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@148766 268f45cc-cd09-0410-ab3c-d52691b4dbfc