Reduce usage of MessageLoopProxy in base/

base/prefs/json_pref_store.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 BASE_PREFS_JSON_PREF_STORE_H_
 #define BASE_PREFS_JSON_PREF_STORE_H_
 
 #include <set>
 #include <string>
 
@@ skipping 26 matching lines @@
       public base::ImportantFileWriter::DataSerializer,
       public base::SupportsWeakPtr<JsonPrefStore> {
  public:
   // Returns instance of SequencedTaskRunner which guarantees that file
   // operations on the same file will be executed in sequenced order.
   static scoped_refptr<base::SequencedTaskRunner> GetTaskRunnerForFile(
       const base::FilePath& pref_filename,
       base::SequencedWorkerPool* worker_pool);
 
   // Same as the constructor below with no alternate filename.
-  JsonPrefStore(const base::FilePath& pref_filename,
-                base::SequencedTaskRunner* sequenced_task_runner,
-                scoped_ptr<PrefFilter> pref_filter);
+  JsonPrefStore(
+      const base::FilePath& pref_filename,
+      const scoped_refptr<base::SequencedTaskRunner>& sequenced_task_runner,
+      scoped_ptr<PrefFilter> pref_filter);
 
   // |sequenced_task_runner| must be a shutdown-blocking task runner, ideally
   // created by the GetTaskRunnerForFile() method above.
   // |pref_filename| is the path to the file to read prefs from.
   // |pref_alternate_filename| is the path to an alternate file which the
   // desired prefs may have previously been written to. If |pref_filename|
   // doesn't exist and |pref_alternate_filename| does, |pref_alternate_filename|
   // will be moved to |pref_filename| before the read occurs.
-  JsonPrefStore(const base::FilePath& pref_filename,
-                const base::FilePath& pref_alternate_filename,
-                base::SequencedTaskRunner* sequenced_task_runner,
-                scoped_ptr<PrefFilter> pref_filter);
+  JsonPrefStore(
+      const base::FilePath& pref_filename,
+      const base::FilePath& pref_alternate_filename,
+      const scoped_refptr<base::SequencedTaskRunner>& sequenced_task_runner,
+      scoped_ptr<PrefFilter> pref_filter);
 
   // PrefStore overrides:
   virtual bool GetValue(const std::string& key,
                         const base::Value** result) const OVERRIDE;
   virtual void AddObserver(PrefStore::Observer* observer) OVERRIDE;
   virtual void RemoveObserver(PrefStore::Observer* observer) OVERRIDE;
   virtual bool HasObservers() const OVERRIDE;
   virtual bool IsInitializationComplete() const OVERRIDE;
 
   // PersistentPrefStore overrides:
@@ skipping 73 matching lines @@
   bool initialized_;
   bool filtering_in_progress_;
   PrefReadError read_error_;
 
   std::set<std::string> keys_need_empty_value_;
 
   DISALLOW_COPY_AND_ASSIGN(JsonPrefStore);
 };
 
 #endif  // BASE_PREFS_JSON_PREF_STORE_H_