Use mirror layer for minimized windows in overview mode

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 244 matching lines @@
       new RoundedRectView(border_radius, SK_ColorTRANSPARENT);
   content_view->set_background(new BackgroundWith1PxBorder(
       background_color, border_color, border_thickness, border_radius));
   widget->SetContentsView(content_view);
   widget_window->GetParent()->StackChildAtTop(widget_window);
   widget->Show();
   widget_window->SetOpacity(initial_opacity);
   return widget;
 }
 
+bool IsMinimizedStateType(wm::WindowStateType type) {
+  return type == wm::WINDOW_STATE_TYPE_DOCKED_MINIMIZED ||
+         type == wm::WINDOW_STATE_TYPE_MINIMIZED;
+}
+
 }  // 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),
+      window_state_observer_(this),
       selected_index_(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);
   }
 
   for (auto* window : windows_in_root) {
     window_observer_.Add(window);
+    window_state_observer_.Add(window->GetWindowState());
     window_list_.push_back(new WindowSelectorItem(window, window_selector_));
   }
 }
 
 WindowGrid::~WindowGrid() {}
 
 void WindowGrid::Shutdown() {
   for (auto iter = window_list_.begin(); iter != window_list_.end(); ++iter)
     (*iter)->Shutdown();
 
@@ skipping 257 matching lines @@
   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_observer_.Remove(window);
+  window_state_observer_.Remove(window->GetWindowState());
   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.
+  // During preparation, window bounds can change. 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);
   PositionWindows(false);
 }
 
+void WindowGrid::OnPostWindowStateTypeChange(wm::WindowState* window_state,
+                                             wm::WindowStateType old_type) {
+  // During preparation, window state can change. (e.g. updating shelf
+  // visibility may show the temporary hidden (minimized) panels.

[varkha, 2016/11/08 00:02:56]

nit: temporarily
nit: mismatched () in the comment.

+  if (!prepared_for_overview_)
+    return;
+
+  wm::WindowStateType new_type = window_state->GetStateType();
+  if (IsMinimizedStateType(old_type) == IsMinimizedStateType(new_type))
+    return;
+
+  auto iter = std::find_if(window_list_.begin(), window_list_.end(),
+                           [window_state](WindowSelectorItem* item) {
+                             return item->Contains(window_state->window());
+                           });
+  if (iter != window_list_.end()) {
+    (*iter)->OnMinimizedStateChanged();
+    PositionWindows(false);
+  }
+}
+
 void WindowGrid::InitShieldWidget() {
   // TODO(varkha): The code assumes that SHELF_BACKGROUND_MAXIMIZED is
   // synonymous with a black shelf background. Update this code if that
   // assumption is no longer valid.
   const float initial_opacity =
       (WmShelf::ForWindow(root_window_)->GetBackgroundType() ==
        SHELF_BACKGROUND_MAXIMIZED)
           ? 1.f
           : 0.f;
   shield_widget_.reset(CreateBackgroundWidget(
@@ skipping 186 matching lines @@
         *min_right = left;
       if (*max_right < left)
         *max_right = left;
     }
     *max_bottom = top + height;
   }
   return windows_fit;
 }
 
 }  // namespace ash