Don't treat minimized windows as lower priority in MRU list (for Alt+Tab

ash/common/wm/overview/window_grid.cc

 // Copyright 2014 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_grid.h"
 
 #include <algorithm>
 #include <functional>
 #include <set>
 #include <utility>
@@ skipping 374 matching lines @@
   return widget;
 }
 
 }  // namespace
 
 WindowGrid::WindowGrid(WmWindow* root_window,
                        const std::vector<WmWindow*>& windows,
                        WindowSelector* window_selector)
     : root_window_(root_window),
       window_selector_(window_selector),
+      window_observer_(this),
       selected_index_(0),
-      num_columns_(0) {
+      num_columns_(0),
+      prepared_for_overview_(false) {
   std::vector<WmWindow*> windows_in_root;
   for (auto* window : windows) {
     if (window->GetRootWindow() == root_window)
       windows_in_root.push_back(window);
   }
 
   if (!ash::MaterialDesignController::IsOverviewMaterial() &&
       base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kAshEnableStableOverviewOrder)) {
     // Reorder windows to try to minimize movement to target overview positions.
     // This also creates a stable window ordering.
     ReorderItemsGreedyLeastMovement(&windows_in_root, root_window_,
                                     window_selector_->text_filter_bottom());
   }
   for (auto* window : windows_in_root) {
-    window->AddObserver(this);
-    observed_windows_.insert(window);
+    window_observer_.Add(window);
     window_list_.push_back(new WindowSelectorItem(window, window_selector_));
   }
 }
 
-WindowGrid::~WindowGrid() {
-  for (WmWindow* window : observed_windows_)
-    window->RemoveObserver(this);
-}
+WindowGrid::~WindowGrid() {}
 
 void WindowGrid::Shutdown() {
   if (shield_widget_) {
     // Fade out the shield widget. This animation continues past the lifetime
     // of |this|.
     WmWindow* widget_window =
         WmLookup::Get()->GetWindowForWidget(shield_widget_.get());
     ui::ScopedLayerAnimationSettings animation_settings(
         widget_window->GetLayer()->GetAnimator());
     animation_settings.SetTransitionDuration(base::TimeDelta::FromMilliseconds(
@@ skipping 14 matching lines @@
         std::move(observer));
     shield_widget->SetOpacity(0.f);
   }
 }
 
 void WindowGrid::PrepareForOverview() {
   if (ash::MaterialDesignController::IsOverviewMaterial())
     InitShieldWidget();
   for (auto iter = window_list_.begin(); iter != window_list_.end(); ++iter)
     (*iter)->PrepareForOverview();
+  prepared_for_overview_ = true;
 }
 
 void WindowGrid::PositionWindowsMD(bool animate) {
   if (window_list_.empty())
     return;
 
   const int kUnlimited = -1;
   const size_t windows_count = window_list_.size();
   const base::CommandLine* command_line =
       base::CommandLine::ForCurrentProcess();
@@ skipping 314 matching lines @@
       WmLookup::Get()->GetWindowForWidget(selection_widget_.get());
   std::unique_ptr<ScopedOverviewAnimationSettings> animation_settings_label =
       ScopedOverviewAnimationSettingsFactory::Get()
           ->CreateOverviewAnimationSettings(
               OverviewAnimationType::OVERVIEW_ANIMATION_CLOSING_SELECTOR_ITEM,
               selection_widget_window);
   selection_widget_->SetOpacity(0.f);
 }
 
 void WindowGrid::OnWindowDestroying(WmWindow* window) {
-  window->RemoveObserver(this);
-  observed_windows_.erase(window);
+  window_observer_.Remove(window);
   ScopedVector<WindowSelectorItem>::iterator iter =
       std::find_if(window_list_.begin(), window_list_.end(),
                    WindowSelectorItemComparator(window));
 
   DCHECK(iter != window_list_.end());
 
   size_t removed_index = iter - window_list_.begin();
   window_list_.erase(iter);
 
   if (empty()) {
@@ skipping 12 matching lines @@
     if (send_focus_alert)
       SelectedWindow()->SendAccessibleSelectionEvent();
   }
 
   PositionWindows(true);
 }
 
 void WindowGrid::OnWindowBoundsChanged(WmWindow* window,
                                        const gfx::Rect& old_bounds,
                                        const gfx::Rect& new_bounds) {
+  // During preparation, window bounds can change (e.g. by unminimizing a
+  // window). Ignore bounds change notifications in this case; we'll reposition
+  // soon.
+  if (!prepared_for_overview_)
+    return;
+
   auto iter = std::find_if(window_list_.begin(), window_list_.end(),
                            WindowSelectorItemComparator(window));
   DCHECK(iter != window_list_.end());
 
   // Immediately finish any active bounds animation.
   window->StopAnimatingProperty(ui::LayerAnimationElement::BOUNDS);
 
   if (ash::MaterialDesignController::IsOverviewMaterial()) {
     PositionWindows(false);
     return;
@@ skipping 217 matching lines @@
         *min_right = left;
       if (*max_right < left)
         *max_right = left;
     }
     *max_bottom = top + height;
   }
   return windows_fit;
 }
 
 }  // namespace ash