Port DictionaryValue to use string16 instead of wstring.

base/json_writer.cc

Index: base/json_writer.cc
===================================================================
--- base/json_writer.cc	(revision 10828)
+++ base/json_writer.cc	(working copy)
@@ -76,7 +76,7 @@
         std::wstring value;
         bool result = node->GetAsString(&value);
         DCHECK(result);
-        AppendQuotedString(value);
+        AppendQuotedString(WideToUTF16Hack(value));
         break;
       }
 
@@ -155,8 +155,8 @@
   }
 }
 
-void JSONWriter::AppendQuotedString(const std::wstring& str) {
-  string_escape::JavascriptDoubleQuote(WideToUTF16Hack(str), true,
+void JSONWriter::AppendQuotedString(const string16& str) {
+  string_escape::JavascriptDoubleQuote(str, true,
                                        json_string_);
 }