Quota: Factor out (Mock)QuotaManagerProxy into its own file for readability

content/public/test/sandbox_file_system_test_helper.cc

 // Copyright 2013 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.
 
 #include "content/public/test/sandbox_file_system_test_helper.h"
 
 #include "base/file_util.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "base/run_loop.h"
 #include "content/public/test/test_file_system_context.h"
 #include "url/gurl.h"
 #include "webkit/browser/fileapi/file_system_context.h"
 #include "webkit/browser/fileapi/file_system_file_util.h"
 #include "webkit/browser/fileapi/file_system_operation_context.h"
 #include "webkit/browser/fileapi/file_system_operation_runner.h"
 #include "webkit/browser/fileapi/file_system_url.h"
 #include "webkit/browser/fileapi/file_system_usage_cache.h"
 #include "webkit/browser/fileapi/sandbox_file_system_backend.h"
 #include "webkit/browser/quota/mock_special_storage_policy.h"
+#include "webkit/browser/quota/quota_manager_proxy.h"
 #include "webkit/common/fileapi/file_system_util.h"
 
 using fileapi::FileSystemContext;
 using fileapi::FileSystemOperationContext;
 using fileapi::FileSystemOperationRunner;
 using fileapi::FileSystemType;
 using fileapi::FileSystemURL;
 
 namespace content {
 
@@ skipping 120 matching lines @@
   file_system_context_->sandbox_delegate()->
       GetBaseDirectoryForOriginAndType(origin_, type_, true /* create */);
 
   // Initialize the usage cache file.
   base::FilePath usage_cache_path = GetUsageCachePath();
   if (!usage_cache_path.empty())
     usage_cache()->UpdateUsage(usage_cache_path, 0);
 }
 
 }  // namespace content