Add chrome://slow for enabling performance tracing for feedback reports.

chrome/browser/resources/chromeos/slow.css

Index: chrome/browser/resources/chromeos/slow.css
diff --git a/chrome/browser/resources/chromeos/slow.css b/chrome/browser/resources/chromeos/slow.css
new file mode 100644
index 0000000000000000000000000000000000000000..4468bfade72de4bde67a82a2e43725d322c49330
--- /dev/null
+++ b/chrome/browser/resources/chromeos/slow.css
@@ -0,0 +1,48 @@
+/* Copyright (c) 2013 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.
+ */
+
+body {
+  background-color: #E6E6E6;
+  font-family: Helvetica, Arial, sans-serif;
+  font-size: 12pt;
+  margin: 50px 40px 20px 40px;
+  text-align: center;
+}
+
+#container {
+  background-color: #fbfbfb;
+  border: 1px solid #AAA;
+  border-bottom: 1px solid #888;
+  border-radius: 3px;
+  box-shadow: 0 2px 2px #AAA;
+  color: #666;
+  margin: auto;
+  max-width: 540px;
+  min-height: 29px;
+  min-width: 200px;
+  padding: 20px 60px;
+  text-align: start;
+}
+
+#container-inner {
+  background-color: #fbfbfb;
+  margin-top: 25px;
+  text-align: center;
+}
+
+button {
+  -webkit-user-select: none;
+  background-image: -webkit-linear-gradient(#ededed, #ededed 38%, #dedede);
+  border: 1px solid rgba(0, 0, 0, 0.25);
+  border-radius: 2px;
+  box-shadow: 0 1px 0 rgba(0, 0, 0, 0.08),
+    inset 0 1px 2px rgba(255, 255, 255, 0.75);
+  margin-top: 10px;
+  min-height: 29px;
+  min-width: 65px;
+  padding: 8px 13px;
+  text-shadow: 0 1px 0 rgb(240, 240, 240);
+}
+