[Quota] Move quota related callbacks to separate file

chrome/browser/browsing_data/browsing_data_quota_helper_impl.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 CHROME_BROWSER_BROWSING_DATA_BROWSING_DATA_QUOTA_HELPER_IMPL_H_
 #define CHROME_BROWSER_BROWSING_DATA_BROWSING_DATA_QUOTA_HELPER_IMPL_H_
 
 #include <map>
 #include <set>
 #include <string>
 #include <utility>
 
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "chrome/browser/browsing_data/browsing_data_quota_helper.h"
 #include "webkit/quota/quota_types.h"
 
+class GURL;
+
 namespace quota {
 class QuotaManager;
 }
 
 // Implementation of BrowsingDataQuotaHelper.  Since a client of
 // BrowsingDataQuotaHelper should live in UI thread and QuotaManager lives in
 // IO thread, we have to communicate over thread using PostTask.
 class BrowsingDataQuotaHelperImpl : public BrowsingDataQuotaHelper {
  public:
   virtual void StartFetching(const FetchResultCallback& callback) OVERRIDE;
@@ skipping 34 matching lines @@
   scoped_refptr<base::MessageLoopProxy> io_thread_;
   base::WeakPtrFactory<BrowsingDataQuotaHelperImpl> weak_factory_;
 
   friend class BrowsingDataQuotaHelper;
   friend class BrowsingDataQuotaHelperTest;
 
   DISALLOW_COPY_AND_ASSIGN(BrowsingDataQuotaHelperImpl);
 };
 
 #endif  // CHROME_BROWSER_BROWSING_DATA_BROWSING_DATA_QUOTA_HELPER_IMPL_H_