Remove obviously unneeded forward declarations in chrome/browser/[abef]*/*.h.

chrome/browser/extensions/extensions_service.h

 // Copyright (c) 2010 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 CHROME_BROWSER_EXTENSIONS_EXTENSIONS_SERVICE_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSIONS_SERVICE_H_
 #pragma once
 
 #include <map>
 #include <set>
@@ skipping 15 matching lines @@
 #include "chrome/browser/extensions/extension_prefs.h"
 #include "chrome/browser/extensions/extension_process_manager.h"
 #include "chrome/browser/extensions/extension_toolbar_model.h"
 #include "chrome/browser/extensions/extensions_quota_service.h"
 #include "chrome/browser/extensions/external_extension_provider.h"
 #include "chrome/browser/extensions/sandboxed_extension_unpacker.h"
 #include "chrome/common/notification_observer.h"
 #include "chrome/common/notification_registrar.h"
 #include "chrome/common/extensions/extension.h"
 
-class Browser;
 class ExtensionsServiceBackend;
 class ExtensionToolbarModel;
 class ExtensionUpdater;
 class GURL;
 class PrefService;
 class Profile;
-class ResourceDispatcherHost;
-class SiteInstance;
 class Version;
 
 // A pending extension is an extension that hasn't been installed yet
 // and is intended to be installed in the next auto-update cycle.  The
 // update URL of a pending extension may be blank, in which case a
 // default one is assumed.
 struct PendingExtensionInfo {
   PendingExtensionInfo(const GURL& update_url,
                        bool is_theme,
                        bool install_silently,
@@ skipping 498 matching lines @@
 
   // A map of all external extension providers.
   typedef std::map<Extension::Location,
                    linked_ptr<ExternalExtensionProvider> > ProviderMap;
   ProviderMap external_extension_providers_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionsServiceBackend);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSIONS_SERVICE_H_