fix(select): value set through property not being propagated to value accessor

Fixes values set through the `value` property not being propagated to the `value` in the `ControlValueAccessor`.

Fixes #10214.

Author: crisbeto

src/material/select/select.spec.ts

@@ -1870,6 +1870,19 @@ describe('MatSelect', () => {
         expect(requiredMarker)
             .not.toBeNull(`Expected label to have an asterisk, as control was required.`);
       }));
+
+      it('should propagate the value set through the `value` property to the form field',
+        fakeAsync(() => {
+          const control = fixture.componentInstance.control;
+
+          expect(control.value).toBeFalsy();
+
+          fixture.componentInstance.select.value = 'pizza-1';
+          fixture.detectChanges();
+
+          expect(control.value).toBe('pizza-1');
+        }));
+
     });
 
     describe('disabled behavior', () => {

src/material/select/select.ts

@@ -432,6 +432,7 @@ export class MatSelect extends _MatSelectMixinBase implements AfterContentInit,
     if (newValue !== this._value) {
       this.writeValue(newValue);
       this._value = newValue;
+      this._onChange(newValue);
     }
   }
   private _value: any;