Add missing requires

Without explicit requires, it is possible that a build would exclude ol.js.

src/ol/renderer/dom/domtilelayerrenderer.js

@@ -10,6 +10,7 @@ goog.require('goog.dom.TagName');
 goog.require('goog.object');
 goog.require('goog.style');
 goog.require('goog.vec.Mat4');
+goog.require('ol');
 goog.require('ol.Coordinate');
 goog.require('ol.Tile');
 goog.require('ol.TileCoord');