Cleanup: Remove more forward declarations in various chrome/browser directories.

chrome/browser/browsing_data_quota_helper.h

 // Copyright (c) 2011 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_BROWSING_DATA_QUOTA_HELPER_H_
 #define CHROME_BROWSER_BROWSING_DATA_QUOTA_HELPER_H_
 #pragma once
 
 #include <list>
 #include <string>
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/message_loop_proxy.h"
 #include "base/time.h"
 #include "content/public/browser/browser_thread.h"
 #include "webkit/quota/quota_types.h"
 
+class BrowsingDataQuotaHelper;
 class Profile;
 
-namespace quota {
-class QuotaManager;
-}
-
-class BrowsingDataQuotaHelper;
-
 struct BrowsingDataQuotaHelperDeleter {
   static void Destruct(const BrowsingDataQuotaHelper* helper);
 };
 
 // This class is an interface class to bridge between Cookies Tree and Unified
 // Quota System.  This class provides a way to get usage and quota information
 // through the instance.
 //
 // Call Create to create an instance for a profile and call StartFetching with
 // a callback to fetch information asynchronously. If result is no longer needed
@@ skipping 41 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(BrowsingDataQuotaHelper);
 };
 
 bool operator <(const BrowsingDataQuotaHelper::QuotaInfo& lhs,
                 const BrowsingDataQuotaHelper::QuotaInfo& rhs);
 bool operator ==(const BrowsingDataQuotaHelper::QuotaInfo& lhs,
                  const BrowsingDataQuotaHelper::QuotaInfo& rhs);
 
 #endif  // CHROME_BROWSER_BROWSING_DATA_QUOTA_HELPER_H_