Translate viewport related meta tags into @viewport descriptors as suggested by the CSS Device Adap…

Source/core/css/resolver/ViewportStyleResolver.h

Index: Source/core/css/resolver/ViewportStyleResolver.h
diff --git a/Source/core/css/resolver/ViewportStyleResolver.h b/Source/core/css/resolver/ViewportStyleResolver.h
index a523bc5cd001739bc17453febabb02d888e77517..00e3a5cb22f5764970fdfb64d589e190dd535959 100644
--- a/Source/core/css/resolver/ViewportStyleResolver.h
+++ b/Source/core/css/resolver/ViewportStyleResolver.h
@@ -50,6 +50,9 @@ public:
 
     ~ViewportStyleResolver();
 
+    bool shouldDisableDesktopWorkarounds() const;
+    bool affectedByViewportChange() const;
+
     void addViewportRule(StyleRuleViewport*);
 
     void clearDocument();
@@ -61,6 +64,7 @@ private:
     float getViewportArgumentValue(CSSPropertyID) const;
 
     Document* m_document;
+    float m_maxPriority;
     RefPtr<MutableStylePropertySet> m_propertySet;
 };