Add forEach() to CSSVariablesMap

Source/core/css/CSSComputedStyleDeclaration.h

Index: Source/core/css/CSSComputedStyleDeclaration.h
diff --git a/Source/core/css/CSSComputedStyleDeclaration.h b/Source/core/css/CSSComputedStyleDeclaration.h
index 1f2a35fad5209caa3baf78e4472b4b7dbb9121fe..a1e0cc80f7d875f98d44a8297fac13ade93586d2 100644
--- a/Source/core/css/CSSComputedStyleDeclaration.h
+++ b/Source/core/css/CSSComputedStyleDeclaration.h
@@ -50,6 +50,22 @@ class CustomFilterParameter;
 enum EUpdateLayout { DoNotUpdateLayout = false, UpdateLayout = true };
 
 class CSSComputedStyleDeclaration : public CSSStyleDeclaration {
+private:
+    class ComputedCSSVariablesIterator : public CSSVariablesIterator {
+    public:
+        virtual ~ComputedCSSVariablesIterator() { }
+        static PassRefPtr<ComputedCSSVariablesIterator> create(const HashMap<AtomicString, String>* variableMap) { return adoptRef(new ComputedCSSVariablesIterator(variableMap)); }
+    private:
+        explicit ComputedCSSVariablesIterator(const HashMap<AtomicString, String>* variableMap);
+        virtual void advance() OVERRIDE;
+        virtual bool atEnd() const OVERRIDE { return m_it == m_end; }
+        virtual AtomicString name() const OVERRIDE;
+        virtual String value() const OVERRIDE;
+        bool m_active;
+        HashMap<AtomicString, String>::const_iterator m_it;
+        HashMap<AtomicString, String>::const_iterator m_end;
+    };
+
 public:
     static PassRefPtr<CSSComputedStyleDeclaration> create(PassRefPtr<Node> node, bool allowVisitedStyle = false, const String& pseudoElementName = String())
     {
@@ -107,6 +123,7 @@ private:
     virtual void setVariableValue(const AtomicString& name, const String& value, ExceptionCode&) OVERRIDE;
     virtual bool removeVariable(const AtomicString& name) OVERRIDE;
     virtual void clearVariables(ExceptionCode&) OVERRIDE;
+    virtual PassRefPtr<CSSVariablesIterator> variablesIterator() const OVERRIDE { return ComputedCSSVariablesIterator::create(variableMap()); }
 
     virtual bool cssPropertyMatches(CSSPropertyID, const CSSValue*) const OVERRIDE;