Update starting animations complete timing on overview exit

Follow-up on CL:1913508. This moves window minimization done during
transition to home when overview exit starts after observers were
notified about overview start animations have been canceled
(as window hiding is actually part of overview exit).

BUG=1024107

Change-Id: I1b5a520b3ef38c8cf2d69f32ea54b5ea94bd7c0c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1915227Reviewed-by: Sammie Quon <sammiequon@chromium.org>
Commit-Queue: Toni Baržić <tbarzic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#715321}

ash/wm/overview/overview_controller.cc

@@ -417,6 +417,10 @@ void OverviewController::ToggleOverview(
 
     overview_session_->set_is_shutting_down(true);
 
+    if (!start_animations_.empty())
+      OnStartingAnimationComplete(/*canceled=*/true);
+    start_animations_.clear();
+
     if (type == OverviewSession::EnterExitOverviewType::kSlideOutExit ||
         type == OverviewSession::EnterExitOverviewType::kFadeOutExit ||
         type == OverviewSession::EnterExitOverviewType::kSwipeFromShelf) {
@@ -437,10 +441,6 @@ void OverviewController::ToggleOverview(
           windows_to_hide_minimize, true);
     }
 
-    if (!start_animations_.empty())
-      OnStartingAnimationComplete(/*canceled=*/true);
-    start_animations_.clear();
-
     // Do not show mask and show during overview shutdown.
     overview_session_->UpdateRoundedCornersAndShadow();