fix(gridUtil): Fixes gridUtil.off.mousewheel event handler

src/js/core/services/ui-grid-util.js

@@ -1280,7 +1280,7 @@ module.service('gridUtil', ['$log', '$window', '$document', '$http', '$templateC
     }
   };
   s.off.mousewheel = function (elm, fn) {
-    var $elm = angular.element(this);
+    var $elm = angular.element(elm);
 
     var cbs = $elm.data('mousewheel-callbacks');
     var handler = cbs[fn];

test/unit/core/services/ui-grid-util.spec.js

@@ -612,4 +612,30 @@ describe('ui.grid.utilService', function() {
       }).not.toThrow();
     });
   });
+
+  describe('on.mousewheel', function() {
+    it('should register a callback on a dom element', function () {
+      var div = document.createElement('div');
+      var $div = angular.element(div);
+      var callback = function(){};
+      gridUtil.on.mousewheel(div, callback);
+      expect(Object.keys($div.data('mousewheel-callbacks')).length).toEqual(1);
+    });
+  });
+
+  describe('off.mousewheel', function() {
+    it('should deregister a callback on a dom element', function () {
+      var div = document.createElement('div');
+      var $div = angular.element(div);
+      var callback1 = function(){return 1;};
+      var callback2 = function(){return 2;};
+      gridUtil.on.mousewheel(div, callback1);
+      gridUtil.on.mousewheel(div, callback2);
+      expect(Object.keys($div.data('mousewheel-callbacks')).length).toEqual(2);
+      gridUtil.off.mousewheel(div, callback1);
+      expect(Object.keys($div.data('mousewheel-callbacks')).length).toEqual(1);
+      gridUtil.off.mousewheel(div, callback2);
+      expect($div.data('mousewheel-callbacks')).toBe(undefined);
+    });
+  });
 });