/**
  * Starts a new activity for the user to buy an item for sale. This method forwards the intent on
  * to the PurchaseObserver (if it exists) because we need to start the activity on the activity
  * stack of the application.
  *
  * @param pendingIntent a PendingIntent that we received from Android Market that will create the
  *     new buy page activity
  * @param intent an intent containing a request id in an extra field that will be passed to the
  *     buy page activity when it is created
  */
 public static void buyPageIntentResponse(PendingIntent pendingIntent, Intent intent) {
   if (sPurchaseObserver == null) {
     if (StoreConfig.debug) {
       Log.d(TAG, "UI is not running");
     }
     return;
   }
   sPurchaseObserver.startBuyPageActivity(pendingIntent, intent);
 }