Fix tab hover card overlapping animation edge case

There is one edge case that "TabHoverCardController::HideHoverCard
-> WidgetFadeAnimator::FadeOut" could be called with an active
fade in animation. WidgetFadeAnimator::Hide would directly close
the card widget in such case. However, there is an active
ui::ThroughputTracker because of the unfinished fade-in animation.
Stop() would be triggered twice in WidgetFadeAnimator::FadeOut
for the edge case. Once from `fade_complete_callbacks_.Notify`
and the other one from WidgetFadeAnimator::OnWidgetDestroying. The
2nd Stop() would cause a crash because the tracker is no longer
valid in ui::Compositor.

This CL fixes the crash by canceling the pending fade-in animation
and resets the tracker for the edge case.

Bug: 1317746
Change-Id: I4b726bc704e1d048949d21644c125129732d07c6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3624098


Commit-Queue: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Dana Fried <dfried@chromium.org>
Cr-Commit-Position: refs/heads/main@{#999429}