Sync Promo: Correctly setup sync

With r107251 the sync promo page stopped loading.

The problem was due to a difference between the sync promo and the options Sign In UI. The options UI calls ShowSetupUI() when showing the sign in overlay. The promo wasn't calling this causing sync not to be setup correctly.

Fix was to match the behavior of the options UI and call ShowSetupUI() when showing the sync promo page.

BUG=
TEST=


Review URL: http://codereview.chromium.org/8416033

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@107757 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/resources/sync_promo.js

@@ -59,6 +59,7 @@ cr.define('sync_promo', function() {
       $('sync-setup-login-promo-column').hidden = false;
       $('promo-skip').hidden = false;
 
+      this.showSetupUI_();
       chrome.send('SyncPromo:Initialize');
 
       var self = this;