Use explicit WebString <-> string16 conversion methods in media files

content/renderer/media/mock_web_rtc_peer_connection_handler_client.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 "content/renderer/media/mock_web_rtc_peer_connection_handler_client.h"
 
 #include "base/logging.h"
 #include "base/strings/utf_string_conversions.h"
 #include "third_party/WebKit/public/platform/WebMediaStream.h"
 #include "third_party/WebKit/public/platform/WebString.h"
 
@@ skipping 14 matching lines @@
       this,
       &MockWebRTCPeerConnectionHandlerClient::didRemoveRemoteStreamWorker));
 }
 
 MockWebRTCPeerConnectionHandlerClient::
 ~MockWebRTCPeerConnectionHandlerClient() {}
 
 void MockWebRTCPeerConnectionHandlerClient::didGenerateICECandidateWorker(
     const blink::WebRTCICECandidate& candidate) {
   if (!candidate.isNull()) {
-    candidate_sdp_ =
-        base::UTF16ToUTF8(base::StringPiece16(candidate.candidate()));
+    candidate_sdp_ = candidate.candidate().utf8();
     candidate_mline_index_ = candidate.sdpMLineIndex();
-    candidate_mid_ = base::UTF16ToUTF8(base::StringPiece16(candidate.sdpMid()));
+    candidate_mid_ = candidate.sdpMid().utf8();
   } else {
     candidate_sdp_ = "";
     candidate_mline_index_ = -1;
     candidate_mid_ = "";
   }
 }
 
 void MockWebRTCPeerConnectionHandlerClient::didAddRemoteStreamWorker(
     const blink::WebMediaStream& stream_descriptor) {
   remote_steam_ = stream_descriptor;
 }
 
 void MockWebRTCPeerConnectionHandlerClient::didRemoveRemoteStreamWorker(
     const blink::WebMediaStream& stream_descriptor) {
   remote_steam_.reset();
 }
 
 }  // namespace content