Bug 1243591 - Create a pref to enable/disable the Synced Tabs UI refresh and enable it for Nightly r=markh

browser/app/profile/firefox.js

@@ -1309,6 +1309,12 @@ pref("services.sync.prefs.sync.signon.rememberSignons", true);
 pref("services.sync.prefs.sync.spellchecker.dictionary", true);
 pref("services.sync.prefs.sync.xpinstall.whitelist.required", true);
 
+#ifdef NIGHTLY_BUILD
+pref("services.sync.syncedTabsUIRefresh", true);
+#else
+pref("services.sync.syncedTabsUIRefresh", false);
+#endif
+
 // Developer edition preferences
 #ifdef MOZ_DEV_EDITION
 sticky_pref("lightweightThemes.selectedThemeID", "firefox-devedition@mozilla.org");

browser/base/content/browser-sets.inc

@@ -190,6 +190,7 @@
     <broadcaster id="sync-reauth-state" hidden="true"/>
     <broadcaster id="viewTabsSidebar" autoCheck="false" sidebartitle="&syncedTabs.sidebar.label;"
                  type="checkbox" group="sidebar"
+                 hidden="true"
                  sidebarurl="chrome://browser/content/syncedtabs/sidebar.xhtml"
                  oncommand="SidebarUI.toggle('viewTabsSidebar');"/>
     <broadcaster id="workOfflineMenuitemState"/>

browser/base/content/browser-syncui.js

@@ -81,6 +81,12 @@ var gSyncUI = {
     let broadcaster = document.getElementById("sync-status");
     broadcaster.setAttribute("label", this._stringBundle.GetStringFromName("syncnow.label"));
 
+    // Initialize the Synced Tabs Sidebar
+    if (Services.prefs.getBoolPref("services.sync.syncedTabsUIRefresh")) {
+      let sidebarBroadcaster = document.getElementById("viewTabsSidebar");
+      sidebarBroadcaster.removeAttribute("hidden");
+    }
+
     this.updateUI();
   },
 

browser/base/content/browser.js

@@ -6498,7 +6498,11 @@ function isTabEmpty(aTab) {
 }
 
 function BrowserOpenSyncTabs() {
-  gSyncUI.openSyncedTabsPanel();
+  if (Services.prefs.getBoolPref("services.sync.syncedTabsUIRefresh")) {
+    gSyncUI.openSyncedTabsPanel();
+  } else {
+    switchToTabHavingURI("about:sync-tabs", true);
+  }
 }
 
 /**