Defer pushing the parent stack in recalcStyle until StyleResolver::styleForElement()

Source/core/css/resolver/StyleResolverParentScope.cpp

Index: Source/core/css/resolver/StyleResolverParentScope.cpp
diff --git a/Source/core/css/Pair.cpp b/Source/core/css/resolver/StyleResolverParentScope.cpp
similarity index 57%
copy from Source/core/css/Pair.cpp
copy to Source/core/css/resolver/StyleResolverParentScope.cpp
index 5362b6b52747f321f8c880c5518db518edd0230f..bde3a362aed64146b76b1b703260b6e6605bdfa7 100644
--- a/Source/core/css/Pair.cpp
+++ b/Source/core/css/resolver/StyleResolverParentScope.cpp
@@ -3,14 +3,11 @@
 // found in the LICENSE file.
 
 #include "config.h"
-#include "core/css/Pair.h"
+
+#include "core/css/resolver/StyleResolverParentScope.h"
 
 namespace WebCore {
 
-void Pair::trace(Visitor* visitor)
-{
-    visitor->trace(m_first);
-    visitor->trace(m_second);
-}
+StyleResolverParentScope* StyleResolverParentScope::s_currentScope = 0;
 
-}
+} // namespace WebCore