Add AsyncStringFeatureParser and use plain

XMLHttpRequest in the KML example

Since the content-type on github.io is application/octet-stream we need
to implement an Async string based parser interface in the KML parser.
Also use plain XmlHttpRequest in the example instead of jQuery Ajax since
the vector-features example also uses that.

src/ol/layer/vectorlayer.js

@@ -350,10 +350,15 @@ ol.layer.Vector.prototype.parseFeatures = function(data, parser, projection) {
   };
 
   if (goog.isString(data)) {
-    goog.asserts.assert(goog.isFunction(parser.readFeaturesFromString),
-        'Expected a parser with readFeaturesFromString method.');
-    features = parser.readFeaturesFromString(data, {callback: callback});
-    addFeatures.call(this, features);
+    if (goog.isFunction(parser.readFeaturesFromStringAsync)) {
+      parser.readFeaturesFromStringAsync(data, goog.bind(addFeatures, this),
+          {callback: callback});
+    } else {
+      goog.asserts.assert(goog.isFunction(parser.readFeaturesFromString),
+          'Expected a parser with readFeaturesFromString method.');
+      features = parser.readFeaturesFromString(data, {callback: callback});
+      addFeatures.call(this, features);
+    }
   } else if (goog.isObject(data)) {
     if (goog.isFunction(parser.readFeaturesFromObjectAsync)) {
       parser.readFeaturesFromObjectAsync(data, goog.bind(addFeatures, this),

src/ol/parser/featureparser.js

@@ -1,4 +1,5 @@
 goog.provide('ol.parser.AsyncObjectFeatureParser');
+goog.provide('ol.parser.AsyncStringFeatureParser');
 goog.provide('ol.parser.DomFeatureParser');
 goog.provide('ol.parser.ObjectFeatureParser');
 goog.provide('ol.parser.ReadFeaturesOptions');
@@ -56,6 +57,23 @@ ol.parser.StringFeatureParser.prototype.readFeaturesFromString =
 
 
 
+/**
+ * @interface
+ */
+ol.parser.AsyncStringFeatureParser = function() {};
+
+
+/**
+ * @param {string} data String data.
+ * @param {function(Array.<ol.Feature>)} callback Callback which is called
+ * after parsing.
+ * @param {ol.parser.ReadFeaturesOptions=} opt_options Feature reading options.
+ */
+ol.parser.AsyncStringFeatureParser.prototype.readFeaturesFromStringAsync =
+    goog.abstractMethod;
+
+
+
 /**
  * @interface
  */

src/ol/parser/kml.js

@@ -21,6 +21,7 @@ goog.require('ol.geom.Point');
 goog.require('ol.geom.Polygon');
 goog.require('ol.geom.SharedVertices');
 goog.require('ol.parser.AsyncObjectFeatureParser');
+goog.require('ol.parser.AsyncStringFeatureParser');
 goog.require('ol.parser.DomFeatureParser');
 goog.require('ol.parser.ReadFeaturesOptions');
 goog.require('ol.parser.StringFeatureParser');
@@ -47,6 +48,7 @@ ol.parser.KMLOptions;
  * @implements {ol.parser.DomFeatureParser}
  * @implements {ol.parser.StringFeatureParser}
  * @implements {ol.parser.AsyncObjectFeatureParser}
+ * @implements {ol.parser.AsyncStringFeatureParser}
  * @param {ol.parser.KMLOptions=} opt_options Optional configuration object.
  * @extends {ol.parser.XML}
  */
@@ -818,6 +820,19 @@ ol.parser.KML.prototype.readFeaturesFromObjectAsync =
 };
 
 
+/**
+ * @param {string} str KML document.
+ * @param {function(Array.<ol.Feature>)} callback Callback which is called
+ * after parsing.
+ * @param {ol.parser.ReadFeaturesOptions=} opt_options Feature reading options.
+ */
+ol.parser.KML.prototype.readFeaturesFromStringAsync =
+    function(str, callback, opt_options) {
+  this.readFeaturesOptions_ = opt_options;
+  this.read(str, callback);
+};
+
+
 /**
  * Parse a KML document provided as a string.
  * @param {string} str KML document.