Fix broken sizeOption when L.point instance (#4636)

spec/suites/layer/marker/MarkerSpec.js

@@ -57,6 +57,22 @@ describe("Marker", function () {
 			expect(icon.style.height).to.be(expectedXY + 'px');
 		});
 
+		it("set the correct x and y size attributes passing a L.Point instance", function () {
+			var expectedXY = 96;
+			var sizedIcon = new L.Icon.Default({
+				iconUrl: icon1._getIconUrl('icon') + '?3',
+				iconSize: L.point(expectedXY, expectedXY)
+			});
+
+			var marker = new L.Marker([0, 0], {icon: sizedIcon});
+			map.addLayer(marker);
+
+			var icon = marker._icon;
+
+			expect(icon.style.width).to.be(expectedXY + 'px');
+			expect(icon.style.height).to.be(expectedXY + 'px');
+		});
+
 		it("changes the icon to another image", function () {
 			var marker = new L.Marker([0, 0], {icon: icon1});
 			map.addLayer(marker);

src/layer/marker/Icon.js

@@ -103,7 +103,7 @@ L.Icon = L.Class.extend({
 		var options = this.options;
 		var sizeOption = options[name + 'Size'];
 
-		if (!L.Util.isArray(sizeOption)) {
+		if (typeof sizeOption === 'number') {
 			sizeOption = [sizeOption, sizeOption];
 		}