diff --git a/src/ol/projection.js b/src/ol/projection.js
index ca3e93ea88..4080127ad5 100644
--- a/src/ol/projection.js
+++ b/src/ol/projection.js
@@ -103,6 +103,14 @@ ol.Projection.prototype.getExtent = function() {
 };
 
 
+/**
+ * @param {ol.Extent} extent Extent.
+ */
+ol.Projection.prototype.setExtent = function(extent) {
+  this.extent_ = extent;
+};
+
+
 /**
  * @param {number} resolution Resolution.
  * @param {ol.Coordinate} point Point.