CloseAll: Refactor for potential performance improvements

This CL adds some quick changes to the toast system implemented in
CloseAll.

First, it has ToastManagerImpl erase the ToastOverlay entry for the root
window when the root window is removed so that we do not have empty
entries for root windows that are no longer in use.

Second, it has MaybeCommitPendingDeskRemoval check if there is a
temporary_removed_desk_ before resetting the temporary_removed_desk_ and
setting in motion the close process for the active toast.

Third, it changes expired_callback_ to a OnceClosure so that the
expired_callback_ is guaranteed to only run once for any one desk
closure. This is important especially with the multi-monitor toasts that
were introduced in Close-All, where each toast would fire the same
RepeatingClosure when they are being destroyed. This also necessitated
moving ownership of the expired_callback to ToastData so that
there is only one owner of the OnceClosure. The destructor for ToastData will then run expired_callback.

Bug: b:258054693, b:258054862, b:258036878
Change-Id: I67bb5eef03eab26e43554f1ecc17a437bf69aa8d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4017921
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Commit-Queue: Ben Becker <benbecker@chromium.org>
Reviewed-by: Ahmed Mehfooz <amehfooz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1071187}

diff --git a/ash/login/login_screen_controller.cc b/ash/login/login_screen_controller.cc
index 8fcf015..e7dabf5 100644
--- a/ash/login/login_screen_controller.cc
+++ b/ash/login/login_screen_controller.cc

@@ -302,7 +302,7 @@
                        base::UTF8ToUTF16(message), ToastData::kInfiniteDuration,
                        /*visible_on_lock_screen=*/true,
                        /*has_dismiss_button=*/true);
-  Shell::Get()->toast_manager()->Show(toast_data);
+  Shell::Get()->toast_manager()->Show(std::move(toast_data));
 }
 
 void LoginScreenController::FocusLoginShelf(bool reverse) {