refactor(animations): ensure compatibility with noImplicitOverride (#42512)

Adds the `override` keyword to the `animations` sources to ensure
 compatibility with `noImplicitOverride`.

PR Close #42512

packages/animations/browser/src/dsl/animation_timeline_builder.ts

@@ -825,18 +825,18 @@ class SubTimelineBuilder extends TimelineBuilder {
   public timings: AnimateTimings;
 
   constructor(
-      driver: AnimationDriver, public element: any, public keyframes: ɵStyleData[],
+      driver: AnimationDriver, element: any, public keyframes: ɵStyleData[],
       public preStyleProps: string[], public postStyleProps: string[], timings: AnimateTimings,
       private _stretchStartingKeyframe: boolean = false) {
     super(driver, element, timings.delay);
     this.timings = {duration: timings.duration, delay: timings.delay, easing: timings.easing};
   }
 
-  containsAnimation(): boolean {
+  override containsAnimation(): boolean {
     return this.keyframes.length > 1;
   }
 
-  buildKeyframes(): AnimationTimelineInstruction {
+  override buildKeyframes(): AnimationTimelineInstruction {
     let keyframes = this.keyframes;
     let {delay, duration, easing} = this.timings;
     if (this._stretchStartingKeyframe && delay) {

packages/animations/browser/src/render/css_keyframes/direct_style_player.ts

@@ -18,7 +18,7 @@ export class DirectStylePlayer extends NoopAnimationPlayer {
     this._styles = hypenatePropsObject(styles);
   }
 
-  init() {
+  override init() {
     if (this.__initialized || !this._startingStyles) return;
     this.__initialized = true;
     Object.keys(this._styles).forEach(prop => {
@@ -27,7 +27,7 @@ export class DirectStylePlayer extends NoopAnimationPlayer {
     super.init();
   }
 
-  play() {
+  override play() {
     if (!this._startingStyles) return;
     this.init();
     Object.keys(this._styles)
@@ -35,7 +35,7 @@ export class DirectStylePlayer extends NoopAnimationPlayer {
     super.play();
   }
 
-  destroy() {
+  override destroy() {
     if (!this._startingStyles) return;
     Object.keys(this._startingStyles).forEach(prop => {
       const value = this._startingStyles![prop];

packages/animations/browser/test/render/timeline_animation_engine_spec.ts

@@ -122,7 +122,7 @@ class SuffixNormalizer extends AnimationStyleNormalizer {
 }
 
 class SuperMockDriver extends MockAnimationDriver {
-  computeStyle(element: any, prop: string, defaultValue?: string): string {
+  override computeStyle(element: any, prop: string, defaultValue?: string): string {
     return '*star*';
   }
 }

packages/animations/browser/testing/src/mock_animation_driver.ts

@@ -77,23 +77,23 @@ export class MockAnimationPlayer extends NoopAnimationPlayer {
   }
 
   /* @internal */
-  init() {
+  override init() {
     super.init();
     this._onInitFns.forEach(fn => fn());
     this._onInitFns = [];
   }
 
-  reset() {
+  override reset() {
     super.reset();
     this.__started = false;
   }
 
-  finish(): void {
+  override finish(): void {
     super.finish();
     this.__finished = true;
   }
 
-  destroy(): void {
+  override destroy(): void {
     super.destroy();
     this.__finished = true;
   }
@@ -101,12 +101,12 @@ export class MockAnimationPlayer extends NoopAnimationPlayer {
   /* @internal */
   triggerMicrotask() {}
 
-  play(): void {
+  override play(): void {
     super.play();
     this.__started = true;
   }
 
-  hasStarted() {
+  override hasStarted() {
     return this.__started;
   }