MD Settings: About page, implementing channel switcher dialog.

chrome/browser/resources/settings/about_page/about_page.js

Index: chrome/browser/resources/settings/about_page/about_page.js
diff --git a/chrome/browser/resources/settings/about_page/about_page.js b/chrome/browser/resources/settings/about_page/about_page.js
index e73128504178068b9ab90af169351b96df3bb80e..2f3e20643447a763da7ac49434982876ef5826f1 100644
--- a/chrome/browser/resources/settings/about_page/about_page.js
+++ b/chrome/browser/resources/settings/about_page/about_page.js
@@ -202,16 +202,8 @@ Polymer({
   isTargetChannelMoreStable_: function() {
     assert(this.currentChannel_.length > 0);
     assert(this.targetChannel_.length > 0);
-
-    // List of channels in increasing stability order.
-    var channelList = [
-      BrowserChannel.DEV,
-      BrowserChannel.BETA,
-      BrowserChannel.STABLE,
-    ];
-    var currentIndex = channelList.indexOf(this.currentChannel_);
-    var targetIndex = channelList.indexOf(this.targetChannel_);
-    return currentIndex < targetIndex;
+    return settings.isTargetChannelMoreStable(
+        this.currentChannel_, this.targetChannel_);
   },
 
   /** @private */