Recalc styles on resize if we have viewport units.

Source/WebCore/dom/DocumentStyleSheetCollection.h

Index: Source/WebCore/dom/DocumentStyleSheetCollection.h
diff --git a/Source/WebCore/dom/DocumentStyleSheetCollection.h b/Source/WebCore/dom/DocumentStyleSheetCollection.h
index 51997fa8e11097c8a34fbd4009f631c14395da60..c7a3d82a1d1bc84fd42be123b8a2ca1e3b54e0dd 100644
--- a/Source/WebCore/dom/DocumentStyleSheetCollection.h
+++ b/Source/WebCore/dom/DocumentStyleSheetCollection.h
@@ -99,6 +99,8 @@ public:
     void setUsesBeforeAfterRulesOverride(bool b) { m_usesBeforeAfterRulesOverride = b; }
     bool usesRemUnits() const { return m_usesRemUnits; }
     void setUsesRemUnit(bool b) { m_usesRemUnits = b; }
+    bool usesViewportUnits() const { return m_usesViewportUnits; }
+    void setUsesViewportUnit(bool b) { m_usesViewportUnits = b; }
 
     void combineCSSFeatureFlags();
     void resetCSSFeatureFlags();
@@ -152,6 +154,7 @@ private:
     bool m_usesBeforeAfterRules;
     bool m_usesBeforeAfterRulesOverride;
     bool m_usesRemUnits;
+    bool m_usesViewportUnits;
 };
 
 }