refactor: add themeable base class

* Introduces a new `MdThemeable` base class that can be extended by different components to automatically support the `color` input.

* This reduces a lot of repeated code in the different components and it also simplifies maintaining.

Closes #2394.

src/demo-app/dialog/dialog-demo.ts

@@ -119,7 +119,7 @@ export class JazzDialog {
 
       <button
         md-button
-        color="secondary"
+        color="accent"
         (click)="showInStackedDialog()">
         Show in Dialog</button>
     </md-dialog-actions>

src/lib/button/button.ts

@@ -10,6 +10,7 @@ import {
   ViewEncapsulation
 } from '@angular/core';
 import {coerceBooleanProperty, FocusOriginMonitor} from '../core';
+import {MdThemeable} from '../core/style/themeable';
 
 
 // TODO(kara): Convert attribute selectors to classes when attr maps become available
@@ -96,8 +97,7 @@ export class MdMiniFabCssMatStyler {}
   encapsulation: ViewEncapsulation.None,
   changeDetection: ChangeDetectionStrategy.OnPush,
 })
-export class MdButton implements OnDestroy {
-  private _color: string;
+export class MdButton extends MdThemeable implements OnDestroy {
 
   /** Whether the button is round. */
   _isRoundButton: boolean = ['icon-button', 'fab', 'mini-fab'].some(suffix => {
@@ -119,32 +119,16 @@ export class MdButton implements OnDestroy {
   get disabled() { return this._disabled; }
   set disabled(value: boolean) { this._disabled = coerceBooleanProperty(value) ? true : null; }
 
-  constructor(private _elementRef: ElementRef, private _renderer: Renderer,
-              private _focusOriginMonitor: FocusOriginMonitor) {
-    this._focusOriginMonitor.monitor(this._elementRef.nativeElement, this._renderer, true);
+  constructor(private _focusOriginMonitor: FocusOriginMonitor, elementRef: ElementRef,
+              renderer: Renderer) {
+    super(renderer, elementRef);
+    this._focusOriginMonitor.monitor(elementRef.nativeElement, renderer, true);
   }
 
   ngOnDestroy() {
     this._focusOriginMonitor.unmonitor(this._elementRef.nativeElement);
   }
 
-  /** The color of the button. Can be `primary`, `accent`, or `warn`. */
-  @Input()
-  get color(): string { return this._color; }
-  set color(value: string) { this._updateColor(value); }
-
-  _updateColor(newColor: string) {
-    this._setElementColor(this._color, false);
-    this._setElementColor(newColor, true);
-    this._color = newColor;
-  }
-
-  _setElementColor(color: string, isAdd: boolean) {
-    if (color != null && color != '') {
-      this._renderer.setElementClass(this._getHostElement(), `mat-${color}`, isAdd);
-    }
-  }
-
   /** Focuses the button. */
   focus(): void {
     this._renderer.invokeElementMethod(this._getHostElement(), 'focus');
@@ -177,7 +161,7 @@ export class MdButton implements OnDestroy {
 })
 export class MdAnchor extends MdButton {
   constructor(elementRef: ElementRef, renderer: Renderer, focusOriginMonitor: FocusOriginMonitor) {
-    super(elementRef, renderer, focusOriginMonitor);
+    super(focusOriginMonitor, elementRef, renderer);
   }
 
   /** @docs-private */

src/lib/checkbox/checkbox.ts

@@ -21,6 +21,7 @@ import {
   RippleRef,
   FocusOriginMonitor,
 } from '../core';
+import {MdThemeable} from '../core/style/themeable';
 
 
 /** Monotonically increasing integer used to auto-generate unique ids for checkbox components. */
@@ -84,7 +85,9 @@ export class MdCheckboxChange {
   encapsulation: ViewEncapsulation.None,
   changeDetection: ChangeDetectionStrategy.OnPush
 })
-export class MdCheckbox implements ControlValueAccessor, AfterViewInit, OnDestroy {
+export class MdCheckbox extends MdThemeable
+    implements ControlValueAccessor, AfterViewInit, OnDestroy {
+
   /**
    * Attached to the aria-label attribute of the host element. In most cases, arial-labelledby will
    * take precedence so this may be omitted.
@@ -178,8 +181,6 @@ export class MdCheckbox implements ControlValueAccessor, AfterViewInit, OnDestro
 
   private _indeterminate: boolean = false;
 
-  private _color: string;
-
   private _controlValueAccessorChangeFn: (value: any) => void = (value) => {};
 
   /** Reference to the focused state ripple. */
@@ -188,10 +189,13 @@ export class MdCheckbox implements ControlValueAccessor, AfterViewInit, OnDestro
   /** Reference to the focus origin monitor subscription. */
   private _focusedSubscription: Subscription;
 
-  constructor(private _renderer: Renderer,
-              private _elementRef: ElementRef,
-              private _changeDetectorRef: ChangeDetectorRef,
-              private _focusOriginMonitor: FocusOriginMonitor) {
+  constructor(
+    private _changeDetectorRef: ChangeDetectorRef,
+    private _focusOriginMonitor: FocusOriginMonitor,
+    renderer: Renderer,
+    elementRef: ElementRef
+  ) {
+    super(renderer, elementRef);
     this.color = 'accent';
   }
 
@@ -261,23 +265,6 @@ export class MdCheckbox implements ControlValueAccessor, AfterViewInit, OnDestro
     }
   }
 
-  /** The color of the button. Can be `primary`, `accent`, or `warn`. */
-  @Input()
-  get color(): string { return this._color; }
-  set color(value: string) { this._updateColor(value); }
-
-  _updateColor(newColor: string) {
-    this._setElementColor(this._color, false);
-    this._setElementColor(newColor, true);
-    this._color = newColor;
-  }
-
-  _setElementColor(color: string, isAdd: boolean) {
-    if (color != null && color != '') {
-      this._renderer.setElementClass(this._elementRef.nativeElement, `mat-${color}`, isAdd);
-    }
-  }
-
   _isRippleDisabled() {
     return this.disableRipple || this.disabled;
   }

src/lib/chips/chip.ts

@@ -11,6 +11,7 @@ import {
 
 import {Focusable} from '../core/a11y/focus-key-manager';
 import {coerceBooleanProperty} from '../core/coercion/boolean-property';
+import {MdThemeable} from '../core/style/themeable';
 
 export interface MdChipEvent {
   chip: MdChip;
@@ -35,17 +36,14 @@ export interface MdChipEvent {
     '(click)': '_handleClick($event)'
   }
 })
-export class MdChip implements Focusable, OnInit, OnDestroy {
+export class MdChip extends MdThemeable implements Focusable, OnInit, OnDestroy {
 
   /** Whether or not the chip is disabled. Disabled chips cannot be focused. */
   protected _disabled: boolean = null;
 
   /** Whether or not the chip is selected. */
   protected _selected: boolean = false;
 
-  /** The palette color of selected chips. */
-  protected _color: string = 'primary';
-
   /** Emitted when the chip is focused. */
   onFocus = new EventEmitter<MdChipEvent>();
 
@@ -58,11 +56,15 @@ export class MdChip implements Focusable, OnInit, OnDestroy {
   /** Emitted when the chip is destroyed. */
   @Output() destroy = new EventEmitter<MdChipEvent>();
 
-  constructor(protected _renderer: Renderer, protected _elementRef: ElementRef) { }
+  constructor(renderer: Renderer, elementRef: ElementRef) {
+    super(renderer, elementRef);
+
+    // By default the chip elements should use the primary palette.
+    this.color = 'primary';
+  }
 
   ngOnInit(): void {
     this._addDefaultCSSClass();
-    this._updateColor(this._color);
   }
 
   ngOnDestroy(): void {
@@ -108,15 +110,6 @@ export class MdChip implements Focusable, OnInit, OnDestroy {
     return this.selected;
   }
 
-  /** The color of the chip. Can be `primary`, `accent`, or `warn`. */
-  @Input() get color(): string {
-    return this._color;
-  }
-
-  set color(value: string) {
-    this._updateColor(value);
-  }
-
   /** Allows for programmatic focusing of the chip. */
   focus(): void {
     this._renderer.invokeElementMethod(this._elementRef.nativeElement, 'focus');
@@ -148,17 +141,4 @@ export class MdChip implements Focusable, OnInit, OnDestroy {
     }
   }
 
-  /** Updates the private _color variable and the native element. */
-  private _updateColor(newColor: string) {
-    this._setElementColor(this._color, false);
-    this._setElementColor(newColor, true);
-    this._color = newColor;
-  }
-
-  /** Sets the mat-color on the native element. */
-  private _setElementColor(color: string, isAdd: boolean) {
-    if (color != null && color != '') {
-      this._renderer.setElementClass(this._elementRef.nativeElement, `mat-${color}`, isAdd);
-    }
-  }
 }

src/lib/core/selection/pseudo-checkbox/pseudo-checkbox.ts

@@ -5,6 +5,7 @@ import {
   ElementRef,
   Renderer,
 } from '@angular/core';
+import {MdThemeable} from '../../style/themeable';
 
 export type MdPseudoCheckboxState = 'unchecked' | 'checked' | 'indeterminate';
 
@@ -32,29 +33,15 @@ export type MdPseudoCheckboxState = 'unchecked' | 'checked' | 'indeterminate';
     '[class.mat-pseudo-checkbox-disabled]': 'disabled',
   },
 })
-export class MdPseudoCheckbox {
+export class MdPseudoCheckbox extends MdThemeable {
   /** Display state of the checkbox. */
   @Input() state: MdPseudoCheckboxState = 'unchecked';
 
   /** Whether the checkbox is disabled. */
   @Input() disabled: boolean = false;
 
-  /** Color of the checkbox. */
-  @Input()
-  get color(): string { return this._color; };
-  set color(value: string) {
-    if (value) {
-      let nativeElement = this._elementRef.nativeElement;
-
-      this._renderer.setElementClass(nativeElement, `mat-${this.color}`, false);
-      this._renderer.setElementClass(nativeElement, `mat-${value}`, true);
-      this._color = value;
-    }
-  }
-
-  private _color: string;
-
-  constructor(private _elementRef: ElementRef, private _renderer: Renderer) {
+  constructor(elementRef: ElementRef, renderer: Renderer) {
+    super(renderer, elementRef);
     this.color = 'accent';
   }
 }

src/lib/core/style/themeable.spec.ts

@@ -0,0 +1,79 @@
+import {async, ComponentFixture, TestBed} from '@angular/core/testing';
+import {Component, ElementRef, Renderer} from '@angular/core';
+import {MdThemeable} from './themeable';
+import {By} from '@angular/platform-browser';
+
+describe('MdThemeable', () => {
+
+  let fixture: ComponentFixture<TestComponent>;
+  let testComponent: TestComponent;
+  let themeableElement: HTMLElement;
+
+  beforeEach(async(() => {
+    TestBed.configureTestingModule({
+      declarations: [TestComponent, ThemeableComponent],
+    });
+
+    TestBed.compileComponents();
+  }));
+
+  beforeEach(() => {
+    fixture = TestBed.createComponent(TestComponent);
+    fixture.detectChanges();
+
+    testComponent = fixture.componentInstance;
+    themeableElement = fixture.debugElement.query(By.css('themeable-test')).nativeElement;
+  });
+
+  it('should support a default component color', () => {
+    expect(themeableElement.classList).toContain('mat-warn');
+  });
+
+  it('should update classes on color change', () => {
+    expect(themeableElement.classList).toContain('mat-warn');
+
+    testComponent.color = 'primary';
+    fixture.detectChanges();
+
+    expect(themeableElement.classList).toContain('mat-primary');
+    expect(themeableElement.classList).not.toContain('mat-warn');
+
+    testComponent.color = 'accent';
+    fixture.detectChanges();
+
+    expect(themeableElement.classList).toContain('mat-accent');
+    expect(themeableElement.classList).not.toContain('mat-warn');
+    expect(themeableElement.classList).not.toContain('mat-primary');
+
+    testComponent.color = null;
+    fixture.detectChanges();
+
+    expect(themeableElement.classList).not.toContain('mat-accent');
+    expect(themeableElement.classList).not.toContain('mat-warn');
+    expect(themeableElement.classList).not.toContain('mat-primary');
+  });
+
+  it('should throw an error when using an invalid color', () => {
+    testComponent.color = 'Invalid';
+
+    expect(() => fixture.detectChanges()).toThrow();
+  });
+
+});
+
+@Component({
+  selector: 'themeable-test',
+  template: '<span>Themeable</span>'
+})
+class ThemeableComponent extends MdThemeable {
+  constructor(renderer: Renderer, elementRef: ElementRef) {
+    super(renderer, elementRef);
+  }
+}
+
+@Component({
+  template: '<themeable-test [color]="color"></themeable-test>'
+})
+class TestComponent {
+  color: string = 'warn';
+}