Implemented new channel switcher UI.

chrome/browser/resources/help/channel_change_page.css

Index: chrome/browser/resources/help/channel_change_page.css
diff --git a/chrome/browser/resources/help/channel_change_page.css b/chrome/browser/resources/help/channel_change_page.css
new file mode 100644
index 0000000000000000000000000000000000000000..908dca05557021cea28ef81e87ebf646b54b2e20
--- /dev/null
+++ b/chrome/browser/resources/help/channel_change_page.css
@@ -0,0 +1,34 @@
+/* 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.
+ */
+
+#channel-change-page {
+  min-height: 200px;
+  width: 500px;
+}
+
+.channel-change-page-channel label {
+  margin-left: 10px;
+}
+
+.channel-change-page-channel {
+  display: block;
+  margin: 15px 25px;
+}
+
+.show-when-selected-channel-requires-powerwash,
+.show-when-selected-channel-requires-delayed-update,
+.show-when-selected-channel-good,
+.show-when-selected-channel-unstable {
+  display: none !important;
+}
+
+.selected-channel-requires-powerwash
+.show-when-selected-channel-requires-powerwash,
+.selected-channel-requires-delayed-update
+.show-when-selected-channel-requires-delayed-update,
+.selected-channel-good .show-when-selected-channel-good,
+.selected-channel-unstable .show-when-selected-channel-unstable {
+  display: block !important;
+}