Add forEach() to CSSVariablesMap

Source/core/css/CSSVariablesIterator.h

Index: Source/core/css/CSSVariablesIterator.h
diff --git a/Source/core/loader/UniqueIdentifier.h b/Source/core/css/CSSVariablesIterator.h
similarity index 78%
copy from Source/core/loader/UniqueIdentifier.h
copy to Source/core/css/CSSVariablesIterator.h
index c1dc5a2b000338f48b787c9292d80ef1671f5600..816f2a3daee8e175222fee09845e6942e7725c2f 100644
--- a/Source/core/loader/UniqueIdentifier.h
+++ b/Source/core/css/CSSVariablesIterator.h
@@ -11,9 +11,6 @@
  * copyright notice, this list of conditions and the following disclaimer
  * in the documentation and/or other materials provided with the
  * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
@@ -28,14 +25,22 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef UniqueIdentifier_h
-#define UniqueIdentifier_h
+#ifndef CSSVariablesIterator_h
+#define CSSVariablesIterator_h
+
+#include "wtf/RefCounted.h"
 
 namespace WebCore {
 
-unsigned long createUniqueIdentifier();
+class CSSVariablesIterator : public RefCounted<CSSVariablesIterator> {
+public:
+    virtual ~CSSVariablesIterator() { }
+    virtual void advance() = 0;
+    virtual bool atEnd() const = 0;
+    virtual AtomicString name() const = 0;
+    virtual String value() const = 0;
+};
 
 }
 
-#endif // UniqueIdentifier_h
-
+#endif // CSSVariablesIterator_h