Bug 587691: need a way to access the original default engine (the normal "defaultEngine" can change if the original is hidden by the user), r=Ryan, a=blocker

netwerk/base/public/nsIBrowserSearchService.idl

@@ -312,17 +312,23 @@ interface nsIBrowserSearchService : nsISupports
   void removeEngine(in nsISearchEngine engine);
 
   /**
-   * The default search engine. May be null if there are no visible
-   * search engines installed.
+   * The default search engine. Returns the first visible engine if the default
+   * engine is hidden. May be null if there are no visible search engines.
    */
   readonly attribute nsISearchEngine defaultEngine;
 
   /**
    * The currently active search engine. May be null if there are no visible
-   * search engines installed.
+   * search engines.
    */
   attribute nsISearchEngine currentEngine;
 
+  /**
+   * The original default engine. This differs from the "defaultEngine"
+   * attribute in that it always returns a given build's default engine,
+   * regardless of whether it is hidden.
+   */
+  readonly attribute nsISearchEngine originalDefaultEngine;
 };
 
 %{ C++

toolkit/components/search/nsSearchService.js

@@ -3356,14 +3356,16 @@ SearchService.prototype = {
     }
   },
 
-  get defaultEngine() {
+  get originalDefaultEngine() {
     const defPref = BROWSER_SEARCH_PREF + "defaultenginename";
-    // Get the default engine - this pref should always exist, but the engine
-    // might be hidden
-    this._defaultEngine = this.getEngineByName(getLocalizedPref(defPref, ""));
-    if (!this._defaultEngine || this._defaultEngine.hidden)
-      this._defaultEngine = this._getSortedEngines(false)[0] || null;
-    return this._defaultEngine;
+    return this.getEngineByName(getLocalizedPref(defPref, ""));
+  },
+
+  get defaultEngine() {
+    let defaultEngine = this.originalDefaultEngine;
+    if (!defaultEngine || defaultEngine.hidden)
+      defaultEngine = this._getSortedEngines(false)[0] || null;
+    return defaultEngine;
   },
 
   get currentEngine() {