Giving the map a getFeatureInfoForPixel method

This method is an entry point for getting feature information.
Renderers can use a hit canvas or defer to a layer (source) to
get matching features for a pixel.

For now this is only implemented for vector layers, and it uses
a bbox query because we cannot refine the result because of
missing geometry intersection functions yet.

src/ol/mapbrowserevent.js

@@ -147,6 +147,12 @@ ol.MapBrowserEventHandler = function(map) {
    */
   this.downListenerKey_ = null;
 
+  /**
+   * @type {?number}
+   * @private
+   */
+  this.moveListenerKey_ = null;
+
   /**
    * @type {Array.<number>}
    * @private
@@ -172,6 +178,9 @@ ol.MapBrowserEventHandler = function(map) {
   this.downListenerKey_ = goog.events.listen(element,
       goog.events.EventType.MOUSEDOWN,
       this.handleMouseDown_, false, this);
+  this.moveListenerKey_ = goog.events.listen(element,
+      goog.events.EventType.MOUSEMOVE,
+      this.relayMouseMove_, false, this);
   // touch events
   this.touchListenerKeys_ = [
     goog.events.listen(element, [
@@ -281,6 +290,19 @@ ol.MapBrowserEventHandler.prototype.handleMouseMove_ = function(browserEvent) {
 };
 
 
+/**
+ * @param {goog.events.BrowserEvent} browserEvent Browser event.
+ * @private
+ */
+ol.MapBrowserEventHandler.prototype.relayMouseMove_ = function(browserEvent) {
+  if (goog.events.hasListener(
+      this.map_, ol.MapBrowserEvent.EventType.MOUSEMOVE)) {
+    this.dispatchEvent(new ol.MapBrowserEvent(
+        ol.MapBrowserEvent.EventType.MOUSEMOVE, this.map_, browserEvent));
+  }
+};
+
+
 /**
  * @param {goog.events.BrowserEvent} browserEvent Browser event.
  * @private
@@ -335,6 +357,7 @@ ol.MapBrowserEventHandler.prototype.handleTouchEnd_ = function(browserEvent) {
 ol.MapBrowserEventHandler.prototype.disposeInternal = function() {
   goog.events.unlistenByKey(this.clickListenerKey_);
   goog.events.unlistenByKey(this.downListenerKey_);
+  goog.events.unlistenByKey(this.moveListenerKey_);
   if (!goog.isNull(this.dragListenerKeys_)) {
     goog.array.forEach(this.dragListenerKeys_, goog.events.unlistenByKey);
     this.dragListenerKeys_ = null;
@@ -360,5 +383,6 @@ ol.MapBrowserEvent.EventType = {
   DRAGEND: 'dragend',
   TOUCHSTART: goog.events.EventType.TOUCHSTART,
   TOUCHMOVE: goog.events.EventType.TOUCHMOVE,
-  TOUCHEND: goog.events.EventType.TOUCHEND
+  TOUCHEND: goog.events.EventType.TOUCHEND,
+  MOUSEMOVE: goog.events.EventType.MOUSEMOVE
 };