Moves maintaining ShellObservers back to Shell

ash/common/wallpaper/wallpaper_controller.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/common/wallpaper/wallpaper_controller.h"
 
 #include <string>
 #include <utility>
 
 #include "ash/common/ash_switches.h"
 #include "ash/common/wallpaper/wallpaper_controller_observer.h"
 #include "ash/common/wallpaper/wallpaper_delegate.h"
 #include "ash/common/wallpaper/wallpaper_view.h"
 #include "ash/common/wallpaper/wallpaper_widget_controller.h"
 #include "ash/common/wm_shell.h"
 #include "ash/common/wm_window.h"
 #include "ash/public/cpp/shell_window_ids.h"
 #include "ash/root_window_controller.h"
+#include "ash/shell.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/task_runner.h"
 #include "components/wallpaper/wallpaper_color_calculator.h"
 #include "components/wallpaper/wallpaper_resizer.h"
 #include "ui/display/manager/managed_display_info.h"
 #include "ui/display/screen.h"
 #include "ui/gfx/color_analysis.h"
 #include "ui/views/widget/widget.h"
@@ skipping 38 matching lines @@
 }
 
 WallpaperController::WallpaperController(
     const scoped_refptr<base::TaskRunner>& task_runner)
     : locked_(false),
       wallpaper_mode_(WALLPAPER_NONE),
       prominent_color_(SK_ColorTRANSPARENT),
       wallpaper_reload_delay_(kWallpaperReloadDelayMs),
       task_runner_(task_runner) {
   WmShell::Get()->AddDisplayObserver(this);
-  WmShell::Get()->AddShellObserver(this);
+  Shell::GetInstance()->AddShellObserver(this);
 }
 
 WallpaperController::~WallpaperController() {
   if (current_wallpaper_)
     current_wallpaper_->RemoveObserver(this);
   if (color_calculator_)
     color_calculator_->RemoveObserver(this);
   WmShell::Get()->RemoveDisplayObserver(this);
-  WmShell::Get()->RemoveShellObserver(this);
+  Shell::GetInstance()->RemoveShellObserver(this);
 }
 
 void WallpaperController::BindRequest(
     mojom::WallpaperControllerRequest request) {
   bindings_.AddBinding(this, std::move(request));
 }
 
 gfx::ImageSkia WallpaperController::GetWallpaper() const {
   if (current_wallpaper_)
     return current_wallpaper_->image();
@@ skipping 250 matching lines @@
     color_calculator_->RemoveObserver(this);
 
   color_calculator_ = base::MakeUnique<wallpaper::WallpaperColorCalculator>(
       GetWallpaper(), luma, saturation, task_runner_);
   color_calculator_->AddObserver(this);
   if (!color_calculator_->StartCalculation())
     SetProminentColor(SK_ColorTRANSPARENT);
 }
 
 }  // namespace ash