fix(autocomplete): disable scroll events for autocomplete wrap layer

At the moment we set the z-index of the `autocomplete-wrap` to `51`, that's why it is usable while an open scrollmask
So we only need to disable the scroll events to prevent scrolling when hovering over the `autocomplete-wrap`

Fixes #6585. Fixes #5230. Fixes #5890. Closes #6589.

src/components/autocomplete/js/autocompleteController.js

@@ -19,7 +19,8 @@ function MdAutocompleteCtrl ($scope, $element, $mdUtil, $mdConstant, $mdTheming,
       selectedItemWatchers = [],
       hasFocus             = false,
       lastCount            = 0,
-      fetchesInProgress    = 0;
+      fetchesInProgress    = 0,
+      enableWrapScroll     = null;
 
   //-- public variables with handlers
   defineProperty('hidden', handleHiddenChange, true);
@@ -247,15 +248,39 @@ function MdAutocompleteCtrl ($scope, $element, $mdUtil, $mdConstant, $mdTheming,
       if (elements) {
         $mdUtil.nextTick(function () {
           $mdUtil.disableScrollAround(elements.ul);
+          enableWrapScroll = disableElementScrollEvents(angular.element(elements.wrap));
         }, false, $scope);
       }
     } else if (hidden && !oldHidden) {
       $mdUtil.nextTick(function () {
         $mdUtil.enableScrolling();
+
+        if (enableWrapScroll) {
+          enableWrapScroll();
+          enableWrapScroll = null;
+        }
       }, false, $scope);
     }
   }
 
+  /**
+   * Disables scrolling for a specific element
+   */
+  function disableElementScrollEvents(element) {
+
+    function preventDefault(e) {
+      e.preventDefault();
+    }
+
+    element.on('wheel', preventDefault);
+    element.on('touchmove', preventDefault);
+
+    return function() {
+      element.off('wheel', preventDefault);
+      element.off('touchmove', preventDefault);
+    }
+  }
+
   /**
    * When the user mouses over the dropdown menu, ignore blur events.
    */