Revert of AppListController refactoring part 3: Switching over to use AppListShower in Ash.

ash/shell.cc

Index: ash/shell.cc
diff --git a/ash/shell.cc b/ash/shell.cc
index 751706c4682cfea6612abfa08dc95390ac6f8c18..b4972ec0a3a2024221a3e77d605e06c855dc8caa 100644
--- a/ash/shell.cc
+++ b/ash/shell.cc
@@ -57,6 +57,7 @@
 #include "ash/system/tray/system_tray_delegate.h"
 #include "ash/system/tray/system_tray_notifier.h"
 #include "ash/utility/partial_screenshot_controller.h"
+#include "ash/wm/app_list_controller.h"
 #include "ash/wm/ash_focus_rules.h"
 #include "ash/wm/ash_native_cursor_manager.h"
 #include "ash/wm/coordinate_conversion.h"
@@ -84,7 +85,6 @@
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
 #include "base/trace_event/trace_event.h"
-#include "ui/app_list/shower/app_list_shower.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/env.h"
 #include "ui/aura/layout_manager.h"
@@ -298,15 +298,19 @@
   // If the context window is not given, show it on the target root window.
   if (!window)
     window = GetTargetRootWindow();
-  delegate_->GetAppListShower()->Show(window);
+  if (!app_list_controller_)
+    app_list_controller_.reset(new AppListController);
+  app_list_controller_->Show(window);
 }
 
 void Shell::DismissAppList() {
-  delegate_->GetAppListShower()->Dismiss();
+  if (!app_list_controller_)
+    return;
+  app_list_controller_->Dismiss();
 }
 
 void Shell::ToggleAppList(aura::Window* window) {
-  if (delegate_->GetAppListShower()->IsVisible()) {
+  if (app_list_controller_ && app_list_controller_->IsVisible()) {
     DismissAppList();
     return;
   }
@@ -315,7 +319,17 @@
 }
 
 bool Shell::GetAppListTargetVisibility() const {
-  return delegate_->GetAppListShower()->GetTargetVisibility();
+  return app_list_controller_.get() &&
+      app_list_controller_->GetTargetVisibility();
+}
+
+aura::Window* Shell::GetAppListWindow() {
+  return app_list_controller_.get() ? app_list_controller_->GetWindow()
+                                    : nullptr;
+}
+
+app_list::AppListView* Shell::GetAppListView() {
+  return app_list_controller_.get() ? app_list_controller_->GetView() : nullptr;
 }
 
 bool Shell::IsSystemModalWindowOpen() const {
@@ -704,6 +718,12 @@
   // need to be removed.
   maximize_mode_controller_.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();
+
 #if defined(OS_CHROMEOS)
   // Destroy the LastWindowClosedLogoutReminder before the
   // LogoutConfirmationController.