Change preference APIs to take std::string instead of const char*.

base/prefs/pref_registry_simple.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_REGISTRY_SIMPLE_H_
 #define BASE_PREFS_PREF_REGISTRY_SIMPLE_H_
 
 #include <string>
 
 #include "base/prefs/base_prefs_export.h"
 #include "base/prefs/pref_registry.h"
 
 namespace base {
 class DictionaryValue;
 class FilePath;
 class ListValue;
 }
 
 // A simple implementation of PrefRegistry.
 class BASE_PREFS_EXPORT PrefRegistrySimple : public PrefRegistry {
  public:
   PrefRegistrySimple();
 
-  void RegisterBooleanPref(const char* path, bool default_value);
-  void RegisterIntegerPref(const char* path, int default_value);
-  void RegisterDoublePref(const char* path, double default_value);
-  void RegisterStringPref(const char* path, const std::string& default_value);
-  void RegisterFilePathPref(const char* path,
+  void RegisterBooleanPref(const std::string& path, bool default_value);
+  void RegisterIntegerPref(const std::string& path, int default_value);
+  void RegisterDoublePref(const std::string& path, double default_value);
+  void RegisterStringPref(const std::string& path,
+                          const std::string& default_value);
+  void RegisterFilePathPref(const std::string& path,
                             const base::FilePath& default_value);
-  void RegisterListPref(const char* path);
-  void RegisterDictionaryPref(const char* path);
-  void RegisterListPref(const char* path, base::ListValue* default_value);
-  void RegisterDictionaryPref(const char* path,
+  void RegisterListPref(const std::string& path);
+  void RegisterDictionaryPref(const std::string& path);
+  void RegisterListPref(const std::string& path,
+                        base::ListValue* default_value);
+  void RegisterDictionaryPref(const std::string& path,
                               base::DictionaryValue* default_value);
-  void RegisterInt64Pref(const char* path,
-                         int64 default_value);
+  void RegisterInt64Pref(const std::string& path, int64 default_value);
 
  private:
   ~PrefRegistrySimple() override;
 
   DISALLOW_COPY_AND_ASSIGN(PrefRegistrySimple);
 };
 
 #endif  // BASE_PREFS_PREF_REGISTRY_SIMPLE_H_