Reset the focus after windows are restored, and grids are shutdown.

ash/common/wm/overview/window_selector.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/common/wm/overview/window_selector.h"
 
 #include <algorithm>
 #include <functional>
 #include <set>
 #include <utility>
@@ skipping 366 matching lines @@
   UpdateShelfVisibility();
 }
 
 // NOTE: The work done in Shutdown() is not done in the destructor because it
 // may cause other, unrelated classes, (ie PanelLayoutManager) to make indirect
 // calls to restoring_minimized_windows() on a partially destructed object.
 void WindowSelector::Shutdown() {
   // Stop observing screen metrics changes first to avoid auto-positioning
   // windows in response to work area changes from window activation.
   display::Screen::GetScreen()->RemoveObserver(this);
-
-  size_t remaining_items = 0;
-  for (std::unique_ptr<WindowGrid>& window_grid : grid_list_) {
-    for (WindowSelectorItem* window_selector_item : window_grid->window_list())
-      window_selector_item->RestoreWindow();
-    remaining_items += window_grid->size();
-  }
-
   // Setting focus after restoring windows' state avoids unnecessary animations.

[varkha, 2016/08/15 23:09:25]

This comment that I have added in
https://codereview.chromium.org/2133333002/diff/60001/ash/common/wm/overview/...
no longer makes sense.

[oshima, 2016/08/16 17:40:03]

Done.

   ResetFocusRestoreWindow(true);
   RemoveAllObservers();
 
   std::vector<WmWindow*> root_windows = WmShell::Get()->GetAllRootWindows();
   for (WmWindow* window : root_windows) {
     // Un-hide the callout widgets for panels. It is safe to call this for
     // root_windows that don't contain any panel windows.
     PanelLayoutManager::Get(window)->SetShowCalloutWidgets(true);
   }
 
-  for (std::unique_ptr<WindowGrid>& window_grid : grid_list_)
+  size_t remaining_items = 0;
+  for (std::unique_ptr<WindowGrid>& window_grid : grid_list_) {
+    for (WindowSelectorItem* window_selector_item : window_grid->window_list())
+      window_selector_item->RestoreWindow();
+    remaining_items += window_grid->size();

[varkha, 2016/08/15 23:09:25]

Hmm. This seems right, I probably did the wrong thing in
https://codereview.chromium.org/2133333002/ when I have moved the loop restoring
windows above the set focus. I have done it for a reason though - there was some
badness that I need to check when restoring and updating the layout of the dock
upon exiting overview with the newly activated window which could be displacing
other items in the dock.
Would be good to make sure we are not regressing on something plainly visible
with the dock. Maybe try docking 3-4 windows, minimizing one of them and then
using overview to restore it thus displacing some other docked window and
causing that window to get minimized. See if this scenario still works as
expected.

[oshima, 2016/08/16 17:40:03]

Thanks for the info. Looks like this has to be after restoring window because
DockedWindowLayoutManager can use wrong window state to re-layuout docked
windows otherwise.

Looks like we can simply move ResetFocusRestoreWindow(true) to the last, and it
looks safe.
I also tested various scenario as well.

     window_grid->Shutdown();
+  }
 
   DCHECK(num_items_ >= remaining_items);
   UMA_HISTOGRAM_COUNTS_100("Ash.WindowSelector.OverviewClosedItems",
                            num_items_ - remaining_items);
   UMA_HISTOGRAM_MEDIUM_TIMES("Ash.WindowSelector.TimeInOverview",
                              base::Time::Now() - overview_start_time_);
 
   // Record metrics related to text filtering.
   UMA_HISTOGRAM_COUNTS_100("Ash.WindowSelector.TextFilteringStringLength",
                            text_filter_string_length_);
@@ skipping 295 matching lines @@
   for (size_t i = 0; i <= grid_list_.size() &&
                      grid_list_[selected_grid_index_]->Move(direction, animate);
        i++) {
     selected_grid_index_ =
         (selected_grid_index_ + display_direction + grid_list_.size()) %
         grid_list_.size();
   }
 }
 
 }  // namespace ash