Change PrefStore::ReadResult to a boolean.

base/prefs/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_PREF_STORE_H_
 #define BASE_PREFS_PREF_STORE_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 18 matching lines @@
    public:
     // Called when the value for the given |key| in the store changes.
     virtual void OnPrefValueChanged(const std::string& key) = 0;
     // Notification about the PrefStore being fully initialized.
     virtual void OnInitializationCompleted(bool succeeded) = 0;
 
    protected:
     virtual ~Observer() {}
   };
 
-  // Return values for GetValue().
-  enum ReadResult {
-    // Value found and returned.
-    READ_OK,
-    // No value present, but skip other pref stores and use default.
-    READ_USE_DEFAULT,
-    // No value present.
-    READ_NO_VALUE,
-  };
-
   PrefStore() {}
 
   // Add and remove observers.
   virtual void AddObserver(Observer* observer) {}
   virtual void RemoveObserver(Observer* observer) {}
   virtual size_t NumberOfObservers() const;
 
   // Whether the store has completed all asynchronous initialization.
   virtual bool IsInitializationComplete() const;
 
   // Get the value for a given preference |key| and stores it in |*result|.
-  // |*result| is only modified if the return value is READ_OK and if |result|
+  // |*result| is only modified if the return value is true and if |result|
   // is not NULL. Ownership of the |*result| value remains with the PrefStore.
-  virtual ReadResult GetValue(const std::string& key,
-                              const base::Value** result) const = 0;
+  virtual bool GetValue(const std::string& key,
+                        const base::Value** result) const = 0;
 
  protected:
   friend class base::RefCounted<PrefStore>;
   virtual ~PrefStore() {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(PrefStore);
 };
 
 #endif  // BASE_PREFS_PREF_STORE_H_