perf(animations): reduce size of animations bundle

before:
animations.umd.js = 33k
animations.umd.min.js = 9.0k

after:
animations.umd.js = 31k
animations.umd.min.js = 7.9k

packages/animations/src/players/animation_player.ts

@@ -10,23 +10,22 @@ import {scheduleMicroTask} from '../util';
 /**
  * @experimental Animation support is experimental.
  */
-export abstract class AnimationPlayer {
-  abstract onDone(fn: () => void): void;
-  abstract onStart(fn: () => void): void;
-  abstract onDestroy(fn: () => void): void;
-  abstract init(): void;
-  abstract hasStarted(): boolean;
-  abstract play(): void;
-  abstract pause(): void;
-  abstract restart(): void;
-  abstract finish(): void;
-  abstract destroy(): void;
-  abstract reset(): void;
-  abstract setPosition(p: any /** TODO #9100 */): void;
-  abstract getPosition(): number;
-  get parentPlayer(): AnimationPlayer|null { throw new Error('NOT IMPLEMENTED: Base Class'); }
-  set parentPlayer(player: AnimationPlayer|null) { throw new Error('NOT IMPLEMENTED: Base Class'); }
-  get totalTime(): number { throw new Error('NOT IMPLEMENTED: Base Class'); }
+export interface AnimationPlayer {
+  onDone(fn: () => void): void;
+  onStart(fn: () => void): void;
+  onDestroy(fn: () => void): void;
+  init(): void;
+  hasStarted(): boolean;
+  play(): void;
+  pause(): void;
+  restart(): void;
+  finish(): void;
+  destroy(): void;
+  reset(): void;
+  setPosition(p: any /** TODO #9100 */): void;
+  getPosition(): number;
+  parentPlayer: AnimationPlayer|null;
+  readonly totalTime: number;
   beforeDestroy?: () => any;
 }
 

tools/public_api_guard/animations/animations.d.ts

@@ -98,23 +98,23 @@ export interface AnimationOptions {
 }
 
 /** @experimental */
-export declare abstract class AnimationPlayer {
+export interface AnimationPlayer {
     beforeDestroy?: () => any;
     parentPlayer: AnimationPlayer | null;
     readonly totalTime: number;
-    abstract destroy(): void;
-    abstract finish(): void;
-    abstract getPosition(): number;
-    abstract hasStarted(): boolean;
-    abstract init(): void;
-    abstract onDestroy(fn: () => void): void;
-    abstract onDone(fn: () => void): void;
-    abstract onStart(fn: () => void): void;
-    abstract pause(): void;
-    abstract play(): void;
-    abstract reset(): void;
-    abstract restart(): void;
-    abstract setPosition(p: any): void;
+    destroy(): void;
+    finish(): void;
+    getPosition(): number;
+    hasStarted(): boolean;
+    init(): void;
+    onDestroy(fn: () => void): void;
+    onDone(fn: () => void): void;
+    onStart(fn: () => void): void;
+    pause(): void;
+    play(): void;
+    reset(): void;
+    restart(): void;
+    setPosition(p: any): void;
 }
 
 /** @experimental */