Make <a ping> work for context menus.

content/renderer/dom_utils.h

+// Copyright (c) 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_RENDERER_DOM_UTILS_H_
+#define CONTENT_RENDERER_DOM_UTILS_H_
+
+namespace blink {
+class WebNode;
+}
+
+namespace content {
+
+class DomUtils {
+ public:
+  // Walks up the DOM, looking for the first parent that represents an <a>.
+  // Returns a null WebNode if no such <a> exists.
+  static blink::WebNode ExtractParentAnchorNode(const blink::WebNode& node);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_DOM_UTILS_H_