Moves maintaining ShellObservers back to Shell

ash/common/wm/workspace/workspace_layout_manager.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/wm/workspace/workspace_layout_manager.h"
 
 #include <algorithm>
 
 #include "ash/common/session/session_state_delegate.h"
 #include "ash/common/shelf/wm_shelf.h"
@@ skipping 23 matching lines @@
 
 namespace ash {
 
 WorkspaceLayoutManager::WorkspaceLayoutManager(WmWindow* window)
     : window_(window),
       root_window_(window->GetRootWindow()),
       root_window_controller_(root_window_->GetRootWindowController()),
       shell_(window_->GetShell()),
       work_area_in_parent_(wm::GetDisplayWorkAreaBoundsInParent(window_)),
       is_fullscreen_(wm::GetWindowForFullscreenMode(window) != nullptr) {
-  shell_->AddShellObserver(this);
+  Shell::GetInstance()->AddShellObserver(this);
   Shell::GetInstance()->activation_client()->AddObserver(this);
   root_window_->aura_window()->AddObserver(this);
   display::Screen::GetScreen()->AddObserver(this);
   DCHECK(window->aura_window()->GetProperty(kSnapChildrenToPixelBoundary));
 }
 
 WorkspaceLayoutManager::~WorkspaceLayoutManager() {
   if (root_window_)
     root_window_->aura_window()->RemoveObserver(this);
   for (WmWindow* window : windows_) {
     wm::WindowState* window_state = window->GetWindowState();
     window_state->RemoveObserver(this);
     window->aura_window()->RemoveObserver(this);
   }
   display::Screen::GetScreen()->RemoveObserver(this);
   Shell::GetInstance()->activation_client()->RemoveObserver(this);
-  shell_->RemoveShellObserver(this);
+  Shell::GetInstance()->RemoveShellObserver(this);
 }
 
 void WorkspaceLayoutManager::SetMaximizeBackdropDelegate(
     std::unique_ptr<WorkspaceLayoutManagerBackdropDelegate> delegate) {
   backdrop_delegate_ = std::move(delegate);
 }
 
 //////////////////////////////////////////////////////////////////////////////
 // WorkspaceLayoutManager, aura::LayoutManager implementation:
 
@@ skipping 289 matching lines @@
 void WorkspaceLayoutManager::UpdateFullscreenState() {
   // TODO(flackr): The fullscreen state is currently tracked per workspace
   // but the shell notification implies a per root window state. Currently
   // only windows in the default workspace container will go fullscreen but
   // this should really be tracked by the RootWindowController since
   // technically any container could get a fullscreen window.
   if (window_->GetShellWindowId() != kShellWindowId_DefaultContainer)
     return;
   bool is_fullscreen = wm::GetWindowForFullscreenMode(window_) != nullptr;
   if (is_fullscreen != is_fullscreen_) {
-    WmShell::Get()->NotifyFullscreenStateChanged(is_fullscreen, root_window_);
+    Shell::GetInstance()->NotifyFullscreenStateChanged(is_fullscreen,
+                                                       root_window_);
     is_fullscreen_ = is_fullscreen;
   }
 }
 
 void WorkspaceLayoutManager::UpdateAlwaysOnTop(WmWindow* window_on_top) {
   // Changing always on top state may change window's parent. Iterate on a copy
   // of |windows_| to avoid invalidating an iterator. Since both workspace and
   // always_on_top containers' layouts are managed by this class all the
   // appropriate windows will be included in the iteration.
   WindowSet windows(windows_);
   for (auto* window : windows) {
     wm::WindowState* window_state = window->GetWindowState();
     if (window_on_top)
       window_state->DisableAlwaysOnTop(window_on_top);
     else
       window_state->RestoreAlwaysOnTop();
   }
 }
 
 }  // namespace ash