Use Blink support to watch CSS selectors directly instead of using a MutationObserver.

content/renderer/render_view_impl.h

 // Copyright (c) 2012 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_RENDER_VIEW_IMPL_H_
 #define CONTENT_RENDERER_RENDER_VIEW_IMPL_H_
 
 #include <deque>
 #include <map>
 #include <set>
@@ skipping 525 matching lines @@
 
   virtual WebKit::WebMediaPlayer* createMediaPlayer(
       WebKit::WebFrame* frame,
       const WebKit::WebURL& url,
       WebKit::WebMediaPlayerClient* client);
   virtual WebKit::WebCookieJar* cookieJar(WebKit::WebFrame* frame);
   virtual void didAccessInitialDocument(WebKit::WebFrame* frame);
   virtual void didDisownOpener(WebKit::WebFrame* frame);
   virtual void frameDetached(WebKit::WebFrame* frame);
   virtual void willClose(WebKit::WebFrame* frame);
+  virtual void didMatchCSS(
+      WebKit::WebFrame* frame,
+      const WebKit::WebVector<WebKit::WebString>& newly_matching_selectors,
+      const WebKit::WebVector<WebKit::WebString>& stopped_matching_selectors);
 
   // The WebDataSource::ExtraData* is assumed to be a DocumentState* subclass.
   virtual WebKit::WebNavigationPolicy decidePolicyForNavigation(
       WebKit::WebFrame* frame,
       WebKit::WebDataSource::ExtraData* extraData,
       const WebKit::WebURLRequest& request,
       WebKit::WebNavigationType type,
       WebKit::WebNavigationPolicy default_policy,
       bool is_redirect);
   // DEPRECATED.
@@ skipping 976 matching lines @@
   // use the Observer interface to filter IPC messages and receive frame change
   // notifications.
   // ---------------------------------------------------------------------------
 
   DISALLOW_COPY_AND_ASSIGN(RenderViewImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_RENDER_VIEW_IMPL_H_