Make UTF16ToASCII and UTF16TOUTF8 take a StringPiece

content/renderer/speech_recognition_dispatcher.cc

Index: content/renderer/speech_recognition_dispatcher.cc
diff --git a/content/renderer/speech_recognition_dispatcher.cc b/content/renderer/speech_recognition_dispatcher.cc
index 0c433e33245f08df4f9618c3f77a5640da19a9a4..67d9fb37823cc4ccd77308bfdc21372ca141c64d 100644
--- a/content/renderer/speech_recognition_dispatcher.cc
+++ b/content/renderer/speech_recognition_dispatcher.cc
@@ -99,7 +99,8 @@ void SpeechRecognitionDispatcher::start(
     msg_params.grammars.push_back(
         SpeechRecognitionGrammar(grammar.src().spec(), grammar.weight()));
   }
-  msg_params.language = base::UTF16ToUTF8(params.language());
+  msg_params.language =
+      base::UTF16ToUTF8(base::StringPiece16(params.language()));
   msg_params.max_hypotheses = static_cast<uint32>(params.maxAlternatives());
   msg_params.continuous = params.continuous();
   msg_params.interim_results = params.interimResults();