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

content/browser/accessibility/accessibility_tree_formatter_mac.mm

 // 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 "content/browser/accessibility/accessibility_tree_formatter.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/basictypes.h"
 #include "base/files/file_path.h"
@@ skipping 249 matching lines @@
       WriteAttribute([defaultAttributes containsObject:requestedAttribute],
                      StringPrintf("%s='%s'",
                                   requestedAttributeUTF8.c_str(),
                                   s_value.c_str()),
                      &line);
       continue;
     }
     const base::Value* value;
     if (dict.Get(requestedAttributeUTF8, &value)) {
       std::string json_value;
-      base::JSONWriter::Write(value, &json_value);
+      base::JSONWriter::Write(*value, &json_value);
       WriteAttribute(
           [defaultAttributes containsObject:requestedAttribute],
           StringPrintf("%s=%s",
                        requestedAttributeUTF8.c_str(),
                        json_value.c_str()),
           &line);
     }
   }
   const base::DictionaryValue* d_value = NULL;
   if (dict.GetDictionary(kPositionDictAttr, &d_value)) {
@@ skipping 34 matching lines @@
 const string AccessibilityTreeFormatter::GetAllowString() {
   return "@MAC-ALLOW:";
 }
 
 // static
 const string AccessibilityTreeFormatter::GetDenyString() {
   return "@MAC-DENY:";
 }
 
 }  // namespace content