Revert "Merge pull request #4344 from bartvde/issue-2844"

This reverts commit e5c44b37c9, reversing
changes made to 7f4c6e3634.

src/ol/imagebase.js

@@ -24,9 +24,7 @@ ol.ImageState = {
  * @constructor
  * @extends {goog.events.EventTarget}
  * @param {ol.Extent} extent Extent.
- * @param {Array.<number>|undefined} resolution Resolution, first value
- *     is the resolution in the x direction, second value is the resolution
- *     in the y direction.
+ * @param {number|undefined} resolution Resolution.
  * @param {number} pixelRatio Pixel ratio.
  * @param {ol.ImageState} state State.
  * @param {Array.<ol.Attribution>} attributions Attributions.
@@ -55,7 +53,7 @@ ol.ImageBase = function(extent, resolution, pixelRatio, state, attributions) {
 
   /**
    * @protected
-   * @type {Array.<number>|undefined}
+   * @type {number|undefined}
    */
   this.resolution = resolution;
 
@@ -109,7 +107,7 @@ ol.ImageBase.prototype.getPixelRatio = function() {
 
 
 /**
- * @return {Array.<number>} Resolution.
+ * @return {number} Resolution.
  */
 ol.ImageBase.prototype.getResolution = function() {
   goog.asserts.assert(this.resolution !== undefined, 'resolution not yet set');