When the window is destroyed, remove windows from the related variables.

There are a few crash issues which could be related with reuse the
destroyed window. The crash issues are hard to reproduce.

This CL modifies the OnWindowDestroying function. Even if the app id is
empty, still check the related structure, e.g.
aura_window_to_app_window_, arc_tracker_, to remove the window from all
related variables to remove the window.

BUG=1128491
BUG=1126493

Change-Id: I842a79f3994b00af08b01c4095b890525655ea87
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2496102
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Nancy Wang <nancylingwang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#820987}