extensions: Cleanup class/struct fwd declarations

extensions/browser/event_router.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 EXTENSIONS_BROWSER_EVENT_ROUTER_H_
 #define EXTENSIONS_BROWSER_EVENT_ROUTER_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 12 matching lines @@
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/render_process_host_observer.h"
 #include "extensions/browser/event_listener_map.h"
 #include "extensions/browser/extension_event_histogram_value.h"
 #include "extensions/browser/extension_registry_observer.h"
 #include "extensions/common/event_filtering_info.h"
 #include "ipc/ipc_sender.h"
 #include "url/gurl.h"
 
 class GURL;
-class PrefService;
 
 namespace content {
 class BrowserContext;
 class RenderProcessHost;
 }
 
 namespace extensions {
-class ActivityLog;
 class Extension;
 class ExtensionHost;
 class ExtensionPrefs;
 class ExtensionRegistry;
 
 struct Event;
-struct EventDispatchInfo;
 struct EventListenerInfo;
 
 class EventRouter : public KeyedService,
                     public content::NotificationObserver,
                     public ExtensionRegistryObserver,
                     public EventListenerMap::Delegate,
                     public content::RenderProcessHostObserver {
  public:
   // These constants convey the state of our knowledge of whether we're in
   // a user-caused gesture as part of DispatchEvent.
@@ skipping 370 matching lines @@
   const std::string event_name;
 
   const std::string extension_id;
   const GURL listener_url;
   content::BrowserContext* browser_context;
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_EVENT_ROUTER_H_