CCA: ESLint: Fix floating promise warning in views/camera/timertick.ts

`cca.py lint --eslintrc .eslintrc_floating_promise.js` error count goes
down from 106 to 103.

Bug: b:172336355
Test: cca.py lint --eslintrc .eslintrc_floating_promise.js
Change-Id: I3ab6b0d2f42ca4218fb42c9687ff007990ebec47
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4314700
Commit-Queue: Pi-Hsun Shih <pihsun@chromium.org>
Reviewed-by: Shik Chen <shik@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1115606}

ash/webui/camera_app_ui/resources/js/animation.ts

@@ -31,13 +31,11 @@ function getAnimations(el: HTMLElement): Animation[] {
  * Cancels the running animation on the element, if any.
  *
  * @param el Target element to cancel animation.
- * @return Promise resolved when the animation is cancelled.
  */
-export async function cancel(el: HTMLElement): Promise<void> {
+export function cancel(el: HTMLElement): void {
   for (const a of getAnimations(el)) {
     a.cancel();
   }
-  await getQueueFor(el).flush();
 }
 
 /**
@@ -50,7 +48,7 @@ export async function cancel(el: HTMLElement): Promise<void> {
  */
 export async function play(
     el: HTMLElement, changeElement?: () => void): Promise<void> {
-  await cancel(el);
+  cancel(el);
   const queue = getQueueFor(el);
   async function job() {
     void el.offsetWidth;  // Force repaint before applying the animation.

ash/webui/camera_app_ui/resources/js/views/camera/timertick.ts

@@ -53,10 +53,12 @@ export function start(): Promise<void> {
       } else {
         const sound = sounds.get(tickCounter);
         if (sound !== undefined) {
-          play(dom.get(sound, HTMLAudioElement));
+          // Not waiting for audio to finish playing.
+          void play(dom.get(sound, HTMLAudioElement));
         }
         tickMsg.textContent = tickCounter + '';
-        animate.play(tickMsg);
+        // Not waiting for animation to finish playing.
+        void animate.play(tickMsg);
         tickTimeout = setTimeout(onTimerTick, 1000);
         tickCounter--;
       }