Bug 1093621 - Enable new tablet UI by default in Nightly (r=mcomella)

mobile/android/base/NewTabletUI.java

@@ -7,12 +7,15 @@ package org.mozilla.gecko;
 import android.content.Context;
 import android.content.SharedPreferences;
 
+import org.mozilla.gecko.AppConstants;
 import org.mozilla.gecko.preferences.GeckoPreferences;
 import org.mozilla.gecko.util.HardwareUtils;
 
 public class NewTabletUI {
-    // This value should be in sync with preferences_display.xml.
-    private static final boolean DEFAULT = false;
+    // This value should be in sync with preferences_display.xml. On non-release
+    // builds, the preference UI will be hidden and the (unused) default
+    // preference UI value will still be 'true'.
+    private static final boolean DEFAULT = !AppConstants.RELEASE_BUILD;
 
     private static Boolean sNewTabletUI;
 

mobile/android/base/resources/xml/preferences_display.xml

@@ -27,7 +27,7 @@
 
     <CheckBoxPreference android:key="android.not_a_preference.new_tablet_ui"
                         android:title="@string/new_tablet_pref"
-                        android:defaultValue="false" />
+                        android:defaultValue="true" />
 
     <PreferenceCategory android:title="@string/pref_category_advanced">