Switch from DRT to content shell.

pkg/unittest/lib/coverage_controller.js

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /**
  * Coverage controller logic - used by coverage test harness to embed tests in
- * DumpRenderTree and extract coverage information.
+ * content shell and extract coverage information.
  */
 
 var LONG_LINE = 60000;
 
 function onReceive(e) {
   if (e.data == 'unittest-suite-done') {
     var s = JSON.stringify(top._$jscoverage);
     var res = '';
-    // DumpRenderTree has a bug on lines longer than 2^16, so we split them
+    // conent shell has a bug on lines longer than 2^16, so we split them
     while (s.length > LONG_LINE) {
       res += s.substr(0, LONG_LINE) + '<br>\n';
       s = s.substr(LONG_LINE);
     }
     res += s;
     window.document.body.innerHTML = res;
     window.layoutTestController.notifyDone();
   }
 }
 
 if (window.layoutTestController) {
   window.layoutTestController.dumpAsText();
   window.layoutTestController.waitUntilDone();
   window.addEventListener("message", onReceive, false);
 }