Check in the thirdparty libs needed for webkitpy.

Tools/Scripts/webkitpy/thirdparty/webpagereplay/perftracker/extension/start.js

Index: Tools/Scripts/webkitpy/thirdparty/webpagereplay/perftracker/extension/start.js
diff --git a/Tools/Scripts/webkitpy/thirdparty/webpagereplay/perftracker/extension/start.js b/Tools/Scripts/webkitpy/thirdparty/webpagereplay/perftracker/extension/start.js
new file mode 100644
index 0000000000000000000000000000000000000000..bdeef77cefbec274e5632c9221a77d5d0d139014
--- /dev/null
+++ b/Tools/Scripts/webkitpy/thirdparty/webpagereplay/perftracker/extension/start.js
@@ -0,0 +1,35 @@
+// Copyright 2010 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+function TryStart() {
+  try {
+    var raw_json_data = document.getElementById('json').textContent;
+    var json = JSON.parse(raw_json_data);
+    var port = chrome.extension.connect();
+    port.postMessage({message: 'start', benchmark: json});
+  }
+  catch(err) {
+    console.log("TryStart retrying after exception: " + err);
+    setTimeout(TryStart, 1000);
+    // TODO(mbelshe): remove me!  This is for debugging.
+    console.log("Body is: " + document.body.innerHTML);
+    return;
+  }
+
+  var status_element = document.getElementById('status');
+  status_element.textContent = "ACK";
+}
+
+// We wait 1s before starting the test just to let chrome warm up better.
+setTimeout(TryStart, 250);