Moves maintaining ShellObservers back to Shell

ash/shelf/shelf_widget_unittest.cc

 // Copyright (c) 2013 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/shelf/shelf_widget.h"
 
 #include "ash/common/shelf/shelf_constants.h"
 #include "ash/common/shelf/shelf_layout_manager.h"
 #include "ash/common/shelf/shelf_view.h"
 #include "ash/common/shelf/wm_shelf.h"
@@ skipping 313 matching lines @@
 }
 
 namespace {
 
 // A ShellObserver that sets the shelf alignment and auto hide behavior when the
 // shelf is created, to simulate ChromeLauncherController's behavior.
 class ShelfInitializer : public ShellObserver {
  public:
   ShelfInitializer(ShelfAlignment alignment, ShelfAutoHideBehavior auto_hide)
       : alignment_(alignment), auto_hide_(auto_hide) {
-    WmShell::Get()->AddShellObserver(this);
+    Shell::GetInstance()->AddShellObserver(this);
   }
-  ~ShelfInitializer() override { WmShell::Get()->RemoveShellObserver(this); }
+  ~ShelfInitializer() override {
+    Shell::GetInstance()->RemoveShellObserver(this);
+  }
 
   // ShellObserver:
   void OnShelfCreatedForRootWindow(WmWindow* root_window) override {
     WmShelf* shelf = root_window->GetRootWindowController()->GetShelf();
     shelf->SetAlignment(alignment_);
     shelf->SetAutoHideBehavior(auto_hide_);
     shelf->UpdateVisibilityState();
   }
 
  private:
@@ skipping 61 matching lines @@
 }
 
 TEST_F(ShelfWidgetTestWithInitializer, CreateLockedShelf) {
   // The auto hide state 'HIDDEN' is returned for any non-auto-hide behavior.
   TestCreateShelfWithInitialValues(SHELF_ALIGNMENT_BOTTOM_LOCKED,
                                    SHELF_AUTO_HIDE_BEHAVIOR_NEVER,
                                    SHELF_VISIBLE, SHELF_AUTO_HIDE_HIDDEN);
 }
 
 }  // namespace ash