WebUI Tab Strip: Fix swiping up bug that replays the entire animation

Previously, if a user swiped up the full 200px and released, the
animation would re-play from the very beginning.

Bug: 1014679
Change-Id: I6810fd371d375b812e206b9e6e8067a5644bf86e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1910872Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Commit-Queue: John Lee <johntlee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#714594}

chrome/browser/resources/tab_strip/tab_swiper.js

@@ -227,7 +227,7 @@ export class TabSwiper {
             (event.timeStamp - this.currentPointerDownEvent_.timeStamp)) >
         SWIPE_VELOCITY_THRESHOLD;
 
-    if (pixelsSwiped === SWIPE_FINISH_THRESHOLD_PX) {
+    if (Math.abs(pixelsSwiped) === SWIPE_FINISH_THRESHOLD_PX) {
       // The user has swiped the max amount of pixels to swipe and the animation
       // has already completed all its keyframes, so just fire the onfinish
       // events on the animation.