fix(select): view not updating when using OnPush detection strategy (#2894)

Fixes the select's view not being updated when the value is set through a component that has its change detection set to `OnPush`.

Fixes #2663.
Fixes #2269.

Author: crisbeto

src/lib/select/select.spec.ts

@@ -1,6 +1,13 @@
 import {TestBed, async, ComponentFixture, fakeAsync, tick} from '@angular/core/testing';
 import {By} from '@angular/platform-browser';
-import {Component, DebugElement, QueryList, ViewChild, ViewChildren} from '@angular/core';
+import {
+  Component,
+  DebugElement,
+  QueryList,
+  ViewChild,
+  ViewChildren,
+  ChangeDetectionStrategy,
+} from '@angular/core';
 import {MdSelectModule} from './index';
 import {OverlayContainer} from '../core/overlay/overlay-container';
 import {MdSelect} from './select';
@@ -26,7 +33,8 @@ describe('MdSelect', () => {
         SelectInitWithoutOptions,
         SelectWithChangeEvent,
         CustomSelectAccessor,
-        CompWithCustomSelect
+        CompWithCustomSelect,
+        BasicSelectOnPush
       ],
       providers: [
         {provide: OverlayContainer, useFactory: () => {
@@ -1255,6 +1263,29 @@ describe('MdSelect', () => {
       expect(fixture.componentInstance.changeListener).toHaveBeenCalledTimes(1);
     });
   });
+
+  describe('with OnPush change detection', () => {
+    let fixture: ComponentFixture<BasicSelectOnPush>;
+    let trigger: HTMLElement;
+
+    beforeEach(() => {
+      fixture = TestBed.createComponent(BasicSelectOnPush);
+      fixture.detectChanges();
+      trigger = fixture.debugElement.query(By.css('.md-select-trigger')).nativeElement;
+    });
+
+    it('should update the trigger based on the value', () => {
+      fixture.componentInstance.control.setValue('pizza-1');
+      fixture.detectChanges();
+
+      expect(trigger.textContent).toContain('Pizza');
+
+      fixture.componentInstance.control.reset();
+      fixture.detectChanges();
+
+      expect(trigger.textContent).not.toContain('Pizza');
+    });
+  });
 });
 
 @Component({
@@ -1433,6 +1464,29 @@ class CompWithCustomSelect {
   @ViewChild(CustomSelectAccessor) customAccessor: CustomSelectAccessor;
 }
 
+@Component({
+  selector: 'basic-select-on-push',
+  changeDetection: ChangeDetectionStrategy.OnPush,
+  template: `
+    <md-select placeholder="Food" [formControl]="control">
+      <md-option *ngFor="let food of foods" [value]="food.value">
+        {{ food.viewValue }}
+      </md-option>
+    </md-select>
+  `
+})
+class BasicSelectOnPush {
+  foods: any[] = [
+    { value: 'steak-0', viewValue: 'Steak' },
+    { value: 'pizza-1', viewValue: 'Pizza' },
+    { value: 'tacos-2', viewValue: 'Tacos' },
+  ];
+  control = new FormControl();
+
+  @ViewChild(MdSelect) select: MdSelect;
+  @ViewChildren(MdOption) options: QueryList<MdOption>;
+}
+
 
 /**
  * TODO: Move this to core testing utility until Angular has event faking

src/lib/select/select.ts

@@ -13,6 +13,7 @@ import {
   Self,
   ViewEncapsulation,
   ViewChild,
+  ChangeDetectorRef,
 } from '@angular/core';
 import {MdOption, MdOptionSelectEvent} from '../core/option/option';
 import {ENTER, SPACE} from '../core/keyboard/keycodes';
@@ -233,8 +234,8 @@ export class MdSelect implements AfterContentInit, ControlValueAccessor, OnDestr
   @Output() change: EventEmitter<MdSelectChange> = new EventEmitter<MdSelectChange>();
 
   constructor(private _element: ElementRef, private _renderer: Renderer,
-              private _viewportRuler: ViewportRuler, @Optional() private _dir: Dir,
-              @Self() @Optional() public _control: NgControl) {
+              private _viewportRuler: ViewportRuler, private _changeDetectorRef: ChangeDetectorRef,
+              @Optional() private _dir: Dir, @Self() @Optional() public _control: NgControl) {
     if (this._control) {
       this._control.valueAccessor = this;
     }
@@ -301,6 +302,7 @@ export class MdSelect implements AfterContentInit, ControlValueAccessor, OnDestr
     }
 
     this._setSelectionByValue(value);
+    this._changeDetectorRef.markForCheck();
   }
 
   /**