addressed comments

Author: mmalerba

src/lib/core/datetime/native-date-adapter.spec.ts

@@ -296,6 +296,14 @@ describe('NativeDateAdapter', () => {
         new Date(2018, FEB, 1), new Date(2018, JAN, 1), new Date(2019, JAN, 1)))
         .toEqual(new Date(2018, FEB, 1));
   });
+
+  it('should count a Date as a date object', () => {
+    expect(adapter.isDateObject(new Date())).toBe(true);
+  });
+
+  it('should not count a string as a date object', () => {
+    expect(adapter.isDateObject('1/1/2017')).toBe(false);
+  });
 });
 
 

src/lib/datepicker/datepicker-input.ts

@@ -100,7 +100,7 @@ export class MdDatepickerInput<D> implements AfterContentInit, ControlValueAcces
   }
   set value(value: D | null) {
     if (value != null && !this._dateAdapter.isDateObject(value)) {
-      throw new Error('Datepicker: value not recognized as a date object by DateAdapter.');
+      throw Error('Datepicker: value not recognized as a date object by DateAdapter.');
     }
     let oldDate = this.value;
     this._renderer.setProperty(this._elementRef.nativeElement, 'value',