Adding a gray semi transparent backdrop behind the topmost window within the default container

ash/shell.cc

 // Copyright (c) 2012 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/shell.h"
 
 #include <algorithm>
 #include <string>
 
 #include "ash/accelerators/accelerator_controller.h"
@@ skipping 364 matching lines @@
 #endif
 }
 
 void Shell::OnCastingSessionStartedOrStopped(bool started) {
 #if defined(OS_CHROMEOS) && defined(USE_X11)
   if (projecting_observer_)
     projecting_observer_->OnCastingSessionStartedOrStopped(started);
 #endif
 }
 
+void Shell::OnOverviewModeStarted() {
+  FOR_EACH_OBSERVER(ShellObserver, observers_, OnOverviewModeStarted());
+}
+
+void Shell::OnOverviewModeEnded() {
+  FOR_EACH_OBSERVER(ShellObserver, observers_, OnOverviewModeEnded());
+}
+
 void Shell::CreateShelf() {
   RootWindowControllerList controllers = GetAllRootWindowControllers();
   for (RootWindowControllerList::iterator iter = controllers.begin();
        iter != controllers.end(); ++iter)
     (*iter)->shelf()->CreateShelf();
 }
 
 void Shell::CreateKeyboard() {
   // TODO(bshe): Primary root window controller may not be the controller to
   // attach virtual keyboard. See http://crbug.com/303429
@@ skipping 35 matching lines @@
 
 void Shell::EnableMaximizeModeWindowManager(bool enable) {
   if (enable && !maximize_mode_window_manager_.get()) {
     maximize_mode_window_manager_.reset(
         new internal::MaximizeModeWindowManager());
   } else if (!enable && maximize_mode_window_manager_.get()) {
     maximize_mode_window_manager_.reset();
   }
 }
 
+bool Shell::IsMaximizeModeWindowManagerEnabled() {
+  return NULL != maximize_mode_window_manager_.get();
+}
+
 void Shell::UpdateShelfVisibility() {
   RootWindowControllerList controllers = GetAllRootWindowControllers();
   for (RootWindowControllerList::iterator iter = controllers.begin();
        iter != controllers.end(); ++iter)
     if ((*iter)->shelf())
       (*iter)->UpdateShelfVisibility();
 }
 
 void Shell::SetShelfAutoHideBehavior(ShelfAutoHideBehavior behavior,
                                      aura::Window* root_window) {
@@ skipping 194 matching lines @@
   RemovePreTargetHandler(toplevel_window_event_handler_.get());
   RemovePostTargetHandler(toplevel_window_event_handler_.get());
   RemovePreTargetHandler(system_gesture_filter_.get());
   RemovePreTargetHandler(keyboard_metrics_filter_.get());
   if (mouse_cursor_filter_)
     RemovePreTargetHandler(mouse_cursor_filter_.get());
 
   // TooltipController is deleted with the Shell so removing its references.
   RemovePreTargetHandler(tooltip_controller_.get());
 
+  // Disable the maximize mode here since it can be destroyed without without
+  // side effects, but needs to be destroyed before the root windows and the
+  // WorkspaceLayoutManager get destroyed.
+  maximize_mode_window_manager_.reset();
+
   // AppList needs to be released before shelf layout manager, which is
   // destroyed with shelf container in the loop below. However, app list
   // container is now on top of shelf container and released after it.
   // TODO(xiyuan): Move it back when app list container is no longer needed.
   app_list_controller_.reset();
 
   // Destroy SystemTrayDelegate before destroying the status area(s).
   system_tray_delegate_->Shutdown();
   system_tray_delegate_.reset();
 
@@ skipping 424 matching lines @@
 ////////////////////////////////////////////////////////////////////////////////
 // Shell, aura::client::ActivationChangeObserver implementation:
 
 void Shell::OnWindowActivated(aura::Window* gained_active,
                               aura::Window* lost_active) {
   if (gained_active)
     target_root_window_ = gained_active->GetRootWindow();
 }
 
 }  // namespace ash