Add opaque flag to ol.source.TileSource

src/ol/source/tilesource.js

@@ -15,6 +15,7 @@ goog.require('ol.tilegrid.TileGrid');
 /**
  * @typedef {{attributions: (Array.<ol.Attribution>|undefined),
  *            extent: (ol.Extent|undefined),
+ *            opaque: (boolean|undefined),
  *            projection: (ol.Projection|undefined),
  *            tileGrid: (ol.tilegrid.TileGrid|undefined)}}
  */
@@ -35,6 +36,13 @@ ol.source.TileSource = function(tileSourceOptions) {
     projection: tileSourceOptions.projection
   });
 
+  /**
+   * @private
+   * @type {boolean}
+   */
+  this.opaque_ = goog.isDef(tileSourceOptions.opaque) ?
+      tileSourceOptions.opaque : false;
+
   /**
    * @protected
    * @type {ol.tilegrid.TileGrid}
@@ -98,6 +106,14 @@ ol.source.TileSource.prototype.findLoadedTiles = function(loadedTilesByZ,
 };
 
 
+/**
+ * @return {boolean} Opaque.
+ */
+ol.source.TileSource.prototype.getOpaque = function() {
+  return this.opaque_;
+};
+
+
 /**
  * @inheritDoc
  */