extensions: Cleanup class/struct fwd declarations

extensions/renderer/content_watcher.h

 // Copyright 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 EXTENSIONS_RENDERER_CONTENT_WATCHER_H_
 #define EXTENSIONS_RENDERER_CONTENT_WATCHER_H_
 
 #include <map>
 #include <set>
 #include <string>
 #include <vector>
 
 #include "third_party/WebKit/public/platform/WebVector.h"
 
 namespace blink {
 class WebFrame;
 class WebLocalFrame;
 class WebString;
 }
 
 namespace extensions {
 class Dispatcher;
-class Extension;
-class NativeHandler;
 
 // Watches the content of WebFrames to notify extensions when they match various
 // patterns.  This class tracks the set of relevant patterns (set by
 // ExtensionMsg_WatchPages) and the set that match on each WebFrame, and sends a
 // ExtensionHostMsg_OnWatchedPageChange whenever a RenderView's set changes.
 //
 // There's one ContentWatcher per Dispatcher rather than per RenderView because
 // WebFrames can move between RenderViews through adoptNode.
 // TODO(devlin): This class isn't OOPI-safe.
 class ContentWatcher {
@@ skipping 29 matching lines @@
   blink::WebVector<blink::WebString> css_selectors_;
 
   // Maps live WebFrames to the set of CSS selectors they match. Blink sends
   // back diffs, which we apply to these sets.
   std::map<blink::WebFrame*, std::set<std::string> > matching_selectors_;
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_RENDERER_CONTENT_WATCHER_H_