mash: Move SystemTrayDelegate ownership to WmShell

ash/system/cast/tray_cast.cc

 // Copyright 2015 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/system/cast/tray_cast.h"
 
 #include "ash/common/session/session_state_delegate.h"
 #include "ash/common/shelf/shelf_types.h"
 #include "ash/common/shelf/wm_shelf_util.h"
 #include "ash/common/system/tray/fixed_sized_image_view.h"
@@ skipping 27 matching lines @@
 
 namespace ash {
 
 namespace {
 
 const size_t kMaximumStatusStringLength = 100;
 const int kStopButtonRightPadding = 18;
 
 // Returns the active CastConfigDelegate instance.
 ash::CastConfigDelegate* GetCastConfigDelegate() {
-  return ash::Shell::GetInstance()
-      ->system_tray_delegate()
-      ->GetCastConfigDelegate();
+  return WmShell::Get()->system_tray_delegate()->GetCastConfigDelegate();
 }
 
 // Helper method to elide the given string to the maximum length. If a string is
 // contains user-input and is displayed, we should elide it.
 // TODO(jdufault): This does not properly trim unicode characters. We should
 // implement this properly by using views::Label::SetElideBehavior(...). See
 // crbug.com/532496.
 base::string16 ElideString(const base::string16& text) {
   base::string16 elided;
   gfx::ElideString(text, kMaximumStatusStringLength, &elided);
@@ skipping 613 matching lines @@
   is_casting_ = started;
   UpdatePrimaryView();
 }
 
 void TrayCast::UpdateAfterShelfAlignmentChange(ShelfAlignment alignment) {
   if (tray_)
     tray_->UpdateAlignment(alignment);
 }
 
 }  // namespace ash