Bug 1012957 - Save about:config changes immediately as made, r=wesj

mobile/android/chrome/content/config.js

@@ -157,6 +157,9 @@ var NewPrefDialog = {
         break;
     }
 
+    // Ensure pref adds flushed to disk immediately
+    Services.prefs.savePrefFile(null);
+
     this.hide();
   },
 
@@ -217,9 +220,6 @@ var AboutConfig = {
   uninit: function AC_uninit() {
     // Remove the prefs observer
     Services.prefs.removeObserver("", this);
-
-    // Ensure pref adds/changes/resets flushed to disk on unload
-    Services.prefs.savePrefFile(null);
   },
 
   // Clear the filterInput value, to display the entire list
@@ -423,6 +423,9 @@ var AboutConfig = {
     // Reset will handle any locked condition
     let pref = this._getPrefForNode(node);
     pref.reset();
+
+    // Ensure pref reset flushed to disk immediately
+    Services.prefs.savePrefFile(null);
   },
 
   // When we want to toggle a bool pref
@@ -539,6 +542,9 @@ Pref.prototype = {
       default:
         Services.prefs.setCharPref(this.name, aPrefValue);
     }
+
+    // Ensure pref change flushed to disk immediately
+    Services.prefs.savePrefFile(null);
   },
 
   get default() {