H264 HW encode using VideoToolbox

chrome/test/data/extensions/api_test/cast_streaming/end_to_end_sender.js

 // Copyright (c) 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.
 
 // This code uses the tab capture and Cast streaming APIs to capture the content
 // and send it to a Cast receiver end-point controlled by
 // CastStreamingApiTest code.  It generates audio/video test patterns that
 // rotate cyclicly, and these test patterns are checked for by an in-process
 // Cast receiver to confirm the correct end-to-end functionality of the Cast
 // streaming API.
@@ skipping 140 matching lines @@
                     udpId, { address: "127.0.0.1", port: recvPort } );
                 var rtpStream = chrome.cast.streaming.rtpStream;
                 var audioParams = rtpStream.getSupportedParams(audioId)[0];
                 audioParams.payload.aesKey = aesKey;
                 audioParams.payload.aesIvMask = aesIvMask;
                 rtpStream.start(audioId, audioParams);
                 var videoParams = rtpStream.getSupportedParams(videoId)[0];
                 videoParams.payload.maxFrameRate = frameRate;
                 videoParams.payload.aesKey = aesKey;
                 videoParams.payload.aesIvMask = aesIvMask;
+                videoParams.payload.codecName = 'VP8';
                 rtpStream.start(videoId, videoParams);
                 renderTestPatternLoop();
                 chrome.test.succeed();
               });
         });
   }
 ]);