Move viewport unit resolution to style recalc time

Source/core/dom/Document.h

Index: Source/core/dom/Document.h
diff --git a/Source/core/dom/Document.h b/Source/core/dom/Document.h
index d289f361e61d273db1911163723ac9d4b9c0d507..5a0f00684abc520f68494148f2b2c2e8fab8f11f 100644
--- a/Source/core/dom/Document.h
+++ b/Source/core/dom/Document.h
@@ -1017,6 +1017,10 @@ public:
     void updateSecurityOrigin(PassRefPtr<SecurityOrigin>);
     PassOwnPtr<LifecycleNotifier<Document> > createLifecycleNotifier();
 
+    void setHasViewportUnits() { m_hasViewportUnits = true; }
+    bool hasViewportUnits() const { return m_hasViewportUnits; }
+    void notifyResizeForViewportUnits();
+
 protected:
     Document(const DocumentInit&, DocumentClassFlags = DefaultDocumentClass);
 
@@ -1311,6 +1315,8 @@ private:
 
     Timer<Document> m_didAssociateFormControlsTimer;
     HashSet<RefPtr<Element> > m_associatedFormControls;
+
+    bool m_hasViewportUnits;
 };
 
 inline void Document::notifyRemovePendingSheetIfNeeded()