refactor(platform-browser): move platform-browser/animations to animations/browser (#15130)

Closes: #15130

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

@@ -0,0 +1,29 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+import {ɵStyleData} from '@angular/animations';
+import {AnimationEngineInstruction, AnimationTransitionInstructionType} from '../render/animation_engine_instruction';
+
+export interface AnimationTimelineInstruction extends AnimationEngineInstruction {
+  keyframes: ɵStyleData[];
+  duration: number;
+  delay: number;
+  totalTime: number;
+  easing: string;
+}
+
+export function createTimelineInstruction(
+    keyframes: ɵStyleData[], duration: number, delay: number,
+    easing: string): AnimationTimelineInstruction {
+  return {
+    type: AnimationTransitionInstructionType.TimelineAnimation,
+    keyframes,
+    duration,
+    delay,
+    totalTime: duration + delay, easing
+  };
+}