Update fade animation logic in the progress bar

This patch updates the fade animation of the progress bar to use
Animators instead of the ViewPropertyAnimator which does not work
in some instances. The visibility issue is resolved and the animation
code is more consistent with the rest of Chromium's code base.

Bug: 946451
Change-Id: Ide1ffcf42a6be374beb03d623f05d50c62a50274
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1557866
Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Matthew Jones <mdjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#648814}