Check in the thirdparty libs needed for webkitpy.

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

Index: Tools/Scripts/webkitpy/thirdparty/webpagereplay/perftracker/extension/script.js
diff --git a/Tools/Scripts/webkitpy/thirdparty/webpagereplay/perftracker/extension/script.js b/Tools/Scripts/webkitpy/thirdparty/webpagereplay/perftracker/extension/script.js
new file mode 100644
index 0000000000000000000000000000000000000000..f809504ddbf6a2d5b4bf077301c53398e9a6198f
--- /dev/null
+++ b/Tools/Scripts/webkitpy/thirdparty/webpagereplay/perftracker/extension/script.js
@@ -0,0 +1,23 @@
+// 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.
+
+
+// Respond to all requests with timing information for this tab.
+chrome.extension.onRequest.addListener(function(request, sender, sendResponse) {
+  var performance = window.performance || window.webkitPerformance;
+  sendResponse({
+    timing: performance.timing,
+    loadTimes: chrome.loadTimes(),
+  });
+});