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

content/renderer/render_frame_impl.cc

 // Copyright 2013 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.
 
 #include "content/renderer/render_frame_impl.h"
 
 #include "base/command_line.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
 #include "content/child/appcache/appcache_dispatcher.h"
@@ skipping 256 matching lines @@
   if (!render_view_->renderer_preferences_.report_frame_name_changes)
     return;
 
   render_view_->Send(
       new ViewHostMsg_UpdateFrameName(render_view_->GetRoutingID(),
                                       frame->identifier(),
                                       !frame->parent(),
                                       UTF16ToUTF8(name)));
 }
 
+void RenderFrameImpl::didMatchCSS(
+    WebKit::WebFrame* frame,
+    const WebKit::WebVector<WebKit::WebString>& newly_matching_selectors,
+    const WebKit::WebVector<WebKit::WebString>& stopped_matching_selectors) {
+  render_view_->didMatchCSS(
+      frame, newly_matching_selectors, stopped_matching_selectors);
+}
+
 void RenderFrameImpl::loadURLExternally(WebKit::WebFrame* frame,
                                         const WebKit::WebURLRequest& request,
                                         WebKit::WebNavigationPolicy policy) {
   loadURLExternally(frame, request, policy, WebString());
 }
 
 void RenderFrameImpl::loadURLExternally(
     WebKit::WebFrame* frame,
     const WebKit::WebURLRequest& request,
     WebKit::WebNavigationPolicy policy,
@@ skipping 582 matching lines @@
 
 void RenderFrameImpl::didLoseWebGLContext(WebKit::WebFrame* frame,
                                           int arb_robustness_status_code) {
   render_view_->Send(new ViewHostMsg_DidLose3DContext(
       GURL(frame->top()->document().securityOrigin().toString()),
       THREE_D_API_TYPE_WEBGL,
       arb_robustness_status_code));
 }
 
 }  // namespace content