Add ol.format.IGC#getExtensions

src/ol/format/igcformat.js

@@ -43,6 +43,13 @@ ol.format.IGC = function(opt_options) {
 goog.inherits(ol.format.IGC, ol.format.Text);
 
 
+/**
+ * @const {Array.<string>}
+ * @private
+ */
+ol.format.IGC.EXTENSIONS_ = ['.igc'];
+
+
 /**
  * @const {RegExp}
  * @private
@@ -65,6 +72,14 @@ ol.format.IGC.H_RECORD_RE_ = /^H.([A-Z]{3}).*?:(.*)/;
 ol.format.IGC.HFDTE_RECORD_RE_ = /^HFDTE(\d{2})(\d{2})(\d{2})/;
 
 
+/**
+ * @inheritDoc
+ */
+ol.format.IGC.prototype.getExtensions = function() {
+  return ol.format.IGC.EXTENSIONS_;
+};
+
+
 /**
  * @inheritDoc
  */