Merge pull request #1033 from AnalyticalGraphicsInc/fixFromDate

Fix `JulianDate.fromDate` input validation.

Author: shunter

Source/Core/JulianDate.js

@@ -339,7 +339,7 @@ define([
      * var julianDate = JulianDate.fromDate(date, TimeStandard.UTC);
      */
     JulianDate.fromDate = function(date, timeStandard) {
-        if (!defined(date) || date === null || isNaN(date.getTime())) {
+        if (!(date instanceof Date) || isNaN(date.getTime())) {
             throw new DeveloperError('date must be a valid JavaScript Date.');
         }
 

Specs/Core/JulianDateSpec.js

@@ -214,30 +214,12 @@ function(JulianDate,
         }).toThrow();
     });
 
-    it('Fail to construct from a null JavaScript Date', function() {
-        expect(function() {
-            return JulianDate.fromDate(null);
-        }).toThrow();
-    });
-
     it('Fail to construct from an invalid JavaScript Date', function() {
         expect(function() {
             return JulianDate.fromDate(new Date(Date.parse('garbage')));
         }).toThrow();
     });
 
-    it('Fail to construct from a non-date JavaScript Date', function() {
-        expect(function() {
-            return JulianDate.fromDate(0);
-        }).toThrow();
-    });
-
-    it('Fail to construct from a JavaScript Date with null time standard', function() {
-        expect(function() {
-            return JulianDate.fromDate(new Date(), null);
-        }).toThrow();
-    });
-
     it('Fail to construct from a JavaScript Date with invalid time standard', function() {
         expect(function() {
             return JulianDate.fromDate(new Date(), 'invalid');