Refactor backdrop that is currently used in the maximized mode.

ash/wm/maximize_mode/maximize_mode_window_manager.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/wm/maximize_mode/maximize_mode_window_manager.h"
 
 #include "ash/ash_switches.h"
 #include "ash/public/cpp/shell_window_ids.h"
 #include "ash/root_window_controller.h"
 #include "ash/session/session_state_delegate.h"
 #include "ash/shell.h"
 #include "ash/shell_port.h"
+#include "ash/wm/maximize_mode/maximize_mode_backdrop_delegate_impl.h"
 #include "ash/wm/maximize_mode/maximize_mode_event_handler.h"
 #include "ash/wm/maximize_mode/maximize_mode_window_state.h"
-#include "ash/wm/maximize_mode/workspace_backdrop_delegate.h"
 #include "ash/wm/mru_window_tracker.h"
 #include "ash/wm/overview/window_selector_controller.h"
 #include "ash/wm/window_state.h"
 #include "ash/wm/window_state_aura.h"
 #include "ash/wm/wm_event.h"
 #include "ash/wm/workspace_controller.h"
 #include "ash/wm_window.h"
 #include "base/command_line.h"
 #include "base/memory/ptr_util.h"
 #include "base/stl_util.h"
@@ skipping 49 matching lines @@
   // At this time ForgetWindow() should already have been called. If not,
   // someone else must have replaced the "window manager's state object".
   DCHECK(!window->aura_window()->HasObserver(this));
 
   auto it = window_state_map_.find(window);
   DCHECK(it != window_state_map_.end());
   window_state_map_.erase(it);
 }
 
 void MaximizeModeWindowManager::OnOverviewModeStarting() {
-  if (backdrops_hidden_)
-    return;
-
-  EnableBackdropBehindTopWindowOnEachDisplay(false);
   SetDeferBoundsUpdates(true);
-  backdrops_hidden_ = true;
 }
 
 void MaximizeModeWindowManager::OnOverviewModeEnded() {
-  if (!backdrops_hidden_)
-    return;
-
-  backdrops_hidden_ = false;
-  EnableBackdropBehindTopWindowOnEachDisplay(true);
   SetDeferBoundsUpdates(false);
 }
 
 void MaximizeModeWindowManager::OnWindowDestroying(aura::Window* window) {
   if (IsContainerWindow(window)) {
     // container window can be removed on display destruction.
     window->RemoveObserver(this);
     observed_container_windows_.erase(window);
   } else if (base::ContainsValue(added_windows_, window)) {
     // Added window was destroyed before being shown.
@@ skipping 86 matching lines @@
                                                         uint32_t) {
   // Nothing to do here.
 }
 
 void MaximizeModeWindowManager::SetIgnoreWmEventsForExit() {
   for (auto& pair : window_state_map_) {
     pair.second->set_ignore_wm_events(true);
   }
 }
 
-MaximizeModeWindowManager::MaximizeModeWindowManager()
-    : backdrops_hidden_(false) {
+MaximizeModeWindowManager::MaximizeModeWindowManager() {
   // The overview mode needs to be ended before the maximize mode is started. To
   // guarantee the proper order, it will be turned off from here.
   CancelOverview();
 
   MaximizeAllWindows();
   AddWindowCreationObservers();
   EnableBackdropBehindTopWindowOnEachDisplay(true);
   display::Screen::GetScreen()->AddObserver(this);
   Shell::Get()->AddShellObserver(this);
   event_handler_ = ShellPort::Get()->CreateMaximizeModeEventHandler();
@@ skipping 86 matching lines @@
   AddWindowCreationObservers();
   EnableBackdropBehindTopWindowOnEachDisplay(true);
 }
 
 bool MaximizeModeWindowManager::IsContainerWindow(aura::Window* window) {
   return base::ContainsKey(observed_container_windows_, window);
 }
 
 void MaximizeModeWindowManager::EnableBackdropBehindTopWindowOnEachDisplay(
     bool enable) {
-  if (backdrops_hidden_)
-    return;
-
   // Inform the WorkspaceLayoutManager that we want to show a backdrop behind
   // the topmost window of its container.
   for (WmWindow* root : ShellPort::Get()->GetAllRootWindows()) {
     RootWindowController* controller = root->GetRootWindowController();
-    WmWindow* default_container =
-        root->GetChildByShellWindowId(kShellWindowId_DefaultContainer);
-    controller->workspace_controller()->SetMaximizeBackdropDelegate(
-        enable ? base::MakeUnique<WorkspaceBackdropDelegate>(default_container)
+    controller->workspace_controller()->SetBackdropDelegate(
+        enable ? base::MakeUnique<MaximizeModeBackdropDelegateImpl>()
                : nullptr);
   }
 }
 
 }  // namespace ash