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

base/values.cc

 // 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.
 
 #include "base/values.h"
 
 #include <string.h>
 
 #include <algorithm>
 #include <ostream>
@@ skipping 403 matching lines @@
 
 void DictionaryValue::SetString(const std::string& path,
                                 const string16& in_value) {
   Set(path, new StringValue(in_value));
 }
 
 void DictionaryValue::SetWithoutPathExpansion(const std::string& key,
                                               Value* in_value) {
   // If there's an existing value here, we need to delete it, because
   // we own all our children.
-  std::pair<ValueMap::iterator, bool> ins_res =
-      dictionary_.insert(std::make_pair(key, in_value));

[Nico, 2014/12/01 16:57:02]

Isn't the lhs better here? It requires on-stack allocation of a pair (which,
since it's a string pair, needs to go to the heap), but it saves a second
traversal of the tree to find the right insertion position.

(I guess it doesn't matter too much either way, unless there's a benchmark
saying otherwise.)

[Georges Khalil, 2014/12/01 20:34:11]

I'm removing this code from the CL, because it doesn't fit with the description
anymore.

I'll have some bench-marking done and resubmit this as a new CL.

-  if (!ins_res.second) {
-    DCHECK_NE(ins_res.first->second, in_value);  // This would be bogus
-    delete ins_res.first->second;
-    ins_res.first->second = in_value;
+  ValueMap::iterator it = dictionary_.find(key);
+  if (it == dictionary_.end()) {
+    dictionary_.insert(std::make_pair(key, in_value));
+  } else {
+    DCHECK_NE(it->second, in_value);  // This would be bogus
+    delete it->second;
+    it->second = in_value;
   }
 }
 
 void DictionaryValue::SetBooleanWithoutPathExpansion(
     const std::string& path, bool in_value) {
   SetWithoutPathExpansion(path, new FundamentalValue(in_value));
 }
 
 void DictionaryValue::SetIntegerWithoutPathExpansion(
     const std::string& path, int in_value) {
@@ skipping 685 matching lines @@
 
 std::ostream& operator<<(std::ostream& out, const Value& value) {
   std::string json;
   JSONWriter::WriteWithOptions(&value,
                                JSONWriter::OPTIONS_PRETTY_PRINT,
                                &json);
   return out << json;
 }
 
 }  // namespace base