Add devicePixelRatio to ol.FrameState

src/ol/framestate.js

@@ -20,6 +20,7 @@ goog.require('ol.layer.LayerState');
  * @typedef {{animate: boolean,
  *            attributions: Object.<string, ol.Attribution>,
  *            coordinateToPixelMatrix: goog.vec.Mat4.Number,
+ *            devicePixelRatio: number,
  *            extent: (null|ol.Extent),
  *            focus: ol.Coordinate,
  *            index: number,

src/ol/map.js

@@ -1076,6 +1076,7 @@ ol.Map.prototype.renderFrame_ = function(time) {
       animate: false,
       attributions: {},
       coordinateToPixelMatrix: this.coordinateToPixelMatrix_,
+      devicePixelRatio: this.devicePixelRatio_,
       extent: null,
       focus: goog.isNull(this.focus_) ? view2DState.center : this.focus_,
       index: this.frameIndex_++,