added mouseover event handler (#6000)

* added mouseover event

* testing mouseover event handler

* added anchor option for marker

* Revert "added anchor option for marker"

src/ui/bind_handlers.js

@@ -33,6 +33,7 @@ module.exports = function bindHandlers(map: Map, options: {}) {
     el.addEventListener('mousedown', onMouseDown, false);
     el.addEventListener('mouseup', onMouseUp, false);
     el.addEventListener('mousemove', onMouseMove, false);
+    el.addEventListener('mouseover', onMouseOver, false);
     el.addEventListener('touchstart', onTouchStart, false);
     el.addEventListener('touchend', onTouchEnd, false);
     el.addEventListener('touchmove', onTouchMove, false);
@@ -80,6 +81,15 @@ module.exports = function bindHandlers(map: Map, options: {}) {
         fireMouseEvent('mousemove', e);
     }
 
+    function onMouseOver(e: MouseEvent) {
+
+        let target: any = e.toElement || e.target;
+        while (target && target !== el) target = target.parentNode;
+        if (target !== el) return;
+
+        fireMouseEvent('mouseover', e);
+    }
+
     function onTouchStart(e: TouchEvent) {
         map.stop();
         fireTouchEvent('touchstart', e);

src/ui/events.js

@@ -20,6 +20,7 @@ export type MapMouseEvent = {
         | 'click'
         | 'dblclick'
         | 'mousemove'
+        | 'mouseover'
         | 'mouseenter'
         | 'mouseleave'
         | 'mouseover'
@@ -130,14 +131,27 @@ export type MapEvent =
     /**
      * Fired when a pointing device (usually a mouse) is moved within the map.
      *
-     * @event mousemove
+     * @event mouseover
      * @memberof Map
      * @instance
      * @property {MapMouseEvent} data
      * @see [Get coordinates of the mouse pointer](https://www.mapbox.com/mapbox-gl-js/example/mouse-position/)
      * @see [Highlight features under the mouse pointer](https://www.mapbox.com/mapbox-gl-js/example/hover-styles/)
      * @see [Display a popup on hover](https://www.mapbox.com/mapbox-gl-js/example/popup-on-hover/)
      */
+    | 'mouseover'
+
+    /**
+     * Fired when a pointing device (usually a mouse) is moved within the map.
+     *
+     * @event mousemove
+     * @memberof Map
+     * @instance
+     * @property {MapMouseEvent} data
+     * @see [Get coordinates of the mouse pointer](https://www.mapbox.com/mapbox-gl-js/example/mouse-position/)
+     * @see [Highlight features under the mouse pointer](https://www.mapbox.com/mapbox-gl-js/example/hover-styles/)
+     * @see [Display a popup on over](https://www.mapbox.com/mapbox-gl-js/example/popup-on-hover/)
+     */
     | 'mousemove'
 
     /**