Reduce invalidation on children-needs-layout containers

Source/core/rendering/LayoutRepainter.cpp

Index: Source/core/rendering/LayoutRepainter.cpp
diff --git a/Source/core/rendering/LayoutRepainter.cpp b/Source/core/rendering/LayoutRepainter.cpp
index 0e1f7791ce75f65c0d9aed0d2a2077bdb2f42991..2aebd1a7ddfe357ac1fefcabf612db53a1beaa93 100644
--- a/Source/core/rendering/LayoutRepainter.cpp
+++ b/Source/core/rendering/LayoutRepainter.cpp
@@ -55,6 +55,9 @@ bool LayoutRepainter::repaintAfterLayout()
     if (RuntimeEnabledFeatures::repaintAfterLayoutEnabled())
         return false;
 
+    if (!m_object.needsLayoutBecauseOfChildren() && m_object.hasNothingToPaint())

[leviw_travelin_and_unemployed, 2014/03/19 17:47:32]

Why bother with the hasNothingToPaint bitfield instead of just querying the
style here?

[Julien - ping for review, 2014/03/20 01:30:33]

Very good point, sir! Changed.

+        return false;
+
     // Hits in compositing/video/video-controls-layer-creation.html
     DisableCompositingQueryAsserts disabler;