🐛 Animation improvements (ampproject#23322)

* animation improvements

* fix types

* welp...

* use scheduleWait_ var instead

extensions/amp-story/1.0/animation.js

@@ -79,23 +79,12 @@ class AnimationRunner {
    *    !../../amp-animation/0.1/web-animations.Builder
    * >} webAnimationBuilderPromise
    * @param {!../../../src/service/vsync-impl.Vsync} vsync
-   * @param {!../../../src/service/timer-impl.Timer} timer
    * @param {!AnimationSequence} sequence
    */
-  constructor(
-    page,
-    animationDef,
-    webAnimationBuilderPromise,
-    vsync,
-    timer,
-    sequence
-  ) {
+  constructor(page, animationDef, webAnimationBuilderPromise, vsync, sequence) {
     /** @private @const */
     this.page_ = page;
 
-    /** @private @const */
-    this.timer_ = timer;
-
     /** @private @const */
     this.vsync_ = vsync;
 
@@ -204,6 +193,7 @@ class AnimationRunner {
     return this.keyframes_.then(keyframes => ({
       keyframes,
       target: this.target_,
+      delay: `${this.delay_}ms`,
       duration: `${this.duration_}ms`,
       easing: this.easing_,
       fill: 'forwards',
@@ -249,10 +239,6 @@ class AnimationRunner {
       promise = promise.then(() => this.sequence_.waitFor(startAfterId));
     }
 
-    if (this.delay_) {
-      promise = promise.then(() => this.timer_.promise(this.delay_));
-    }
-
     return promise;
   }
 
@@ -283,13 +269,25 @@ class AnimationRunner {
 
   /** Pauses the animation. */
   pause() {
+    // Animation hasn't started yet since it's waiting for a sequenced
+    // animation.
+    if (this.scheduledWait_ !== null) {
+      return;
+    }
+
     if (this.runner_) {
       devAssert(this.runner_).pause();
     }
   }
 
   /** Resumes the animation. */
   resume() {
+    // Animation hasn't started yet since it's waiting for a sequenced
+    // animation.
+    if (this.scheduledWait_ !== null) {
+      return;
+    }
+
     if (this.runner_) {
       devAssert(this.runner_).resume();
     }
@@ -429,9 +427,6 @@ export class AnimationManager {
     /** @private @const */
     this.vsync_ = Services.vsyncFor(this.ampdoc_.win);
 
-    /** @private @const */
-    this.timer_ = Services.timerFor(this.ampdoc_.win);
-
     /** @private @const */
     this.builderPromise_ = this.createAnimationBuilderPromise_();
 
@@ -535,7 +530,6 @@ export class AnimationManager {
       animationDef,
       devAssert(this.builderPromise_),
       this.vsync_,
-      this.timer_,
       this.sequence_
     );
   }