Implement URLSearchParams.

Source/core/html/HTMLAnchorElement.h

Index: Source/core/html/HTMLAnchorElement.h
diff --git a/Source/core/html/HTMLAnchorElement.h b/Source/core/html/HTMLAnchorElement.h
index 701470bdfc6258f1c8b9a5a2c33cdbe002481d9e..ced425616417bd9f1315000f4661af478ab0760e 100644
--- a/Source/core/html/HTMLAnchorElement.h
+++ b/Source/core/html/HTMLAnchorElement.h
@@ -56,6 +56,7 @@ enum {
 };
 
 class HTMLAnchorElement : public HTMLElement, public DOMURLUtils {
+    WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(HTMLAnchorElement);
 public:
     static PassRefPtrWillBeRawPtr<HTMLAnchorElement> create(Document&);
 
@@ -83,6 +84,7 @@ public:
     void invalidateCachedVisitedLinkHash() { m_cachedVisitedLinkHash = 0; }
 
     void sendPings(const KURL& destinationURL) const;
+    virtual void trace(Visitor*) OVERRIDE;
 
 protected:
     HTMLAnchorElement(const QualifiedName&, Document&);