CCA: Resolved when animation cancelled in animateOnce().

Bug: 1087777
Test: tast run <DUT> camera.CCAUIIntent

Change-Id: I98bdafe9f131fc5b3e2b8194e9687f9a1b491fda
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2224937
Commit-Queue: Kuo Jen Wei <inker@chromium.org>
Commit-Queue: Shik Chen <shik@chromium.org>
Auto-Submit: Kuo Jen Wei <inker@chromium.org>
Reviewed-by: Shik Chen <shik@chromium.org>
Cr-Commit-Position: refs/heads/master@{#774013}

chrome/browser/resources/chromeos/camera/src/js/util.js

@@ -176,8 +176,8 @@ export function animateCancel(element) {
 /**
  * Waits for animation completed.
  * @param {!HTMLElement} element Element to be animated.
- * @return {!Promise} Promise is resolved/rejected when animation is
- *     completed/cancelled.
+ * @return {!Promise} Promise is resolved when animation is completed or
+ *     cancelled.
  */
 function waitAnimationCompleted(element) {
   return new Promise((resolve, reject) => {
@@ -191,12 +191,11 @@ function waitAnimationCompleted(element) {
       events.forEach(([e, fn]) => element.removeEventListener(e, fn));
       callback();
     };
-    const rejectWithError = () => reject(new Error('Animation is cancelled.'));
     const events = [
       ['transitionrun', onStart], ['animationstart', onStart],
       ['transitionend', (event) => onFinished(event, resolve)],
       ['animationend', (event) => onFinished(event, resolve)],
-      ['transitioncancel', (event) => onFinished(event, rejectWithError)],
+      ['transitioncancel', (event) => onFinished(event, resolve)],
       // animationcancel is not implemented on chrome.
     ];
     events.forEach(([e, fn]) => element.addEventListener(e, fn));