fix(toast): do not auto set any actionKeys (#11510)

provide warning if an action is defined without an actionKey
fix custom toast example to call removeActionKeyListener()

Fixes #11474

Author: Splaktar

src/components/toast/demoCustomUsage/script.js

@@ -34,7 +34,7 @@
     };
   }
 
-  function ToastCtrl($mdToast, $mdDialog, $document) {
+  function ToastCtrl($mdToast, $mdDialog, $document, $scope) {
     var ctrl = this;
     ctrl.keyListenerConfigured = false;
     ctrl.undoKey = UNDO_KEY;
@@ -70,7 +70,7 @@
     };
 
     /**
-     * @param {KeyboardEvent} event
+     * @param {KeyboardEvent} event to handle
      */
     function handleKeyDown(event) {
       if (event.key === 'Escape') {
@@ -92,9 +92,14 @@
     }
 
     function removeActionKeyListener() {
-      $document.off('keydown');
-      ctrl.keyListenerConfigured = false;
+      if (ctrl.keyListenerConfigured) {
+        $document.off('keydown');
+        ctrl.keyListenerConfigured = false;
+      }
     }
-  }
 
+    $scope.$on('$destroy', function() {
+      removeActionKeyListener();
+    });
+  }
 })();