Merge pull request #918 from twpayne/source-change-events

Source change events

src/ol/layer/layer.js

@@ -28,6 +28,9 @@ ol.layer.Layer = function(options) {
    */
   this.source_ = options.source;
 
+  goog.events.listen(this.source_, goog.events.EventType.CHANGE,
+      this.handleSourceChange_, false, this);
+
   if (!this.source_.isReady()) {
     goog.events.listenOnce(this.source_, goog.events.EventType.LOAD,
         this.handleSourceLoad_, false, this);
@@ -78,6 +81,14 @@ ol.layer.Layer.prototype.getSource = function() {
 };
 
 
+/**
+ * @private
+ */
+ol.layer.Layer.prototype.handleSourceChange_ = function() {
+  this.dispatchChangeEvent();
+};
+
+
 /**
  * @private
  */

src/ol/source/source.js

@@ -49,6 +49,14 @@ ol.source.Source = function(options) {
 goog.inherits(ol.source.Source, goog.events.EventTarget);
 
 
+/**
+ * @protected
+ */
+ol.source.Source.prototype.dispatchChangeEvent = function() {
+  this.dispatchEvent(goog.events.EventType.CHANGE);
+};
+
+
 /**
  * @protected
  */