Better type definition

Fixes the `Invalid type(s) for operator IN.` warnings from the closure compiler.

src/ol/source/TileImage.js

@@ -61,13 +61,13 @@ const TileImage = function(options) {
 
   /**
    * @protected
-   * @type {Object.<string, ol.TileCache>}
+   * @type {!Object.<string, ol.TileCache>}
    */
   this.tileCacheForProjection = {};
 
   /**
    * @protected
-   * @type {Object.<string, ol.tilegrid.TileGrid>}
+   * @type {!Object.<string, ol.tilegrid.TileGrid>}
    */
   this.tileGridForProjection = {};
 
@@ -173,8 +173,7 @@ TileImage.prototype.getTileGridForProjection = function(projection) {
   } else {
     const projKey = getUid(projection).toString();
     if (!(projKey in this.tileGridForProjection)) {
-      this.tileGridForProjection[projKey] =
-          getTileGridForProjection(projection);
+      this.tileGridForProjection[projKey] = getTileGridForProjection(projection);
     }
     return /** @type {!ol.tilegrid.TileGrid} */ (this.tileGridForProjection[projKey]);
   }

src/ol/source/UrlTile.js

@@ -63,7 +63,7 @@ const UrlTile = function(options) {
 
   /**
    * @private
-   * @type {Object.<number, boolean>}
+   * @type {!Object.<number, boolean>}
    */
   this.tileLoadingKeys_ = {};
 

src/ol/source/Vector.js

@@ -126,21 +126,21 @@ const VectorSource = function(opt_options) {
 
   /**
    * @private
-   * @type {Object.<string, ol.Feature>}
+   * @type {!Object.<string, ol.Feature>}
    */
   this.nullGeometryFeatures_ = {};
 
   /**
    * A lookup of features by id (the return from feature.getId()).
    * @private
-   * @type {Object.<string, ol.Feature>}
+   * @type {!Object.<string, ol.Feature>}
    */
   this.idIndex_ = {};
 
   /**
    * A lookup of features without id (keyed by ol.getUid(feature)).
    * @private
-   * @type {Object.<string, ol.Feature>}
+   * @type {!Object.<string, ol.Feature>}
    */
   this.undefIdIndex_ = {};
 

src/ol/source/WMTS.js

@@ -288,7 +288,7 @@ WMTS.prototype.updateDimensions = function(dimensions) {
 /**
  * Generate source options from a capabilities object.
  * @param {Object} wmtsCap An object representing the capabilities document.
- * @param {Object} config Configuration properties for the layer.  Defaults for
+ * @param {!Object} config Configuration properties for the layer.  Defaults for
  *                  the layer will apply if not provided.
  *
  * Required config properties: