openlayers/ol3 — pull request #2675 by fredj (2014-09-03 10:51:25+00:00)
Title: Remove undefined from ol.Map#getLayers return type

It's already assumed that the collection is defined in `ol.Map#addLayer` and `ol.Map#removeLayer`.
(with `goog.asserts.assert(goog.isDef(layers));`).