Convert JsonWriter::Write to taking a const ref for the in-param

extensions/browser/api/storage/settings_storage_quota_enforcer.cc

 // Copyright 2014 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 "extensions/browser/api/storage/settings_storage_quota_enforcer.h"
 
 #include "base/bind.h"
 #include "base/json/json_writer.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 20 matching lines @@
 void Allocate(
     const std::string& key,
     const base::Value& value,
     size_t* used_total,
     std::map<std::string, size_t>* used_per_setting) {
   // Calculate the setting size based on its JSON serialization size.
   // TODO(kalman): Does this work with different encodings?
   // TODO(kalman): This is duplicating work that the leveldb delegate
   // implementation is about to do, and it would be nice to avoid this.
   std::string value_as_json;
-  base::JSONWriter::Write(&value, &value_as_json);
+  base::JSONWriter::Write(value, &value_as_json);
   size_t new_size = key.size() + value_as_json.size();
   size_t existing_size = (*used_per_setting)[key];
 
   *used_total += (new_size - existing_size);
   (*used_per_setting)[key] = new_size;
 }
 
 // Frees the allocation of a setting in a record of total and per-setting usage.
 void Free(
     size_t* used_total,
@@ skipping 212 matching lines @@
   }
 
   for (base::DictionaryValue::Iterator it(maybe_settings->settings());
        !it.IsAtEnd();
        it.Advance()) {
     Allocate(it.key(), it.value(), &used_total_, &used_per_setting_);
   }
 }
 
 }  // namespace extensions