mash: Migrate remaining tray observers and notify functions.

ash/system/chromeos/screen_security/screen_capture_tray_item.cc

 // Copyright 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/system/chromeos/screen_security/screen_capture_tray_item.h"
 
 #include <utility>
 
 #include "ash/common/system/system_notifier.h"
+#include "ash/common/system/tray/system_tray_notifier.h"
 #include "ash/common/wm_shell.h"
-#include "ash/shell.h"
 #include "grit/ash_resources.h"
 #include "grit/ash_strings.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/message_center/message_center.h"
 #include "ui/message_center/notification.h"
 
 using message_center::Notification;
 
 namespace ash {
 namespace {
 
 const char kScreenCaptureNotificationId[] = "chrome://screen/capture";
 
 }  // namespace
 
 ScreenCaptureTrayItem::ScreenCaptureTrayItem(SystemTray* system_tray)
     : ScreenTrayItem(system_tray) {
   WmShell::Get()->AddShellObserver(this);
-  Shell::GetInstance()->system_tray_notifier()->
-      AddScreenCaptureObserver(this);
+  WmShell::Get()->system_tray_notifier()->AddScreenCaptureObserver(this);
 }
 
 ScreenCaptureTrayItem::~ScreenCaptureTrayItem() {
   WmShell::Get()->RemoveShellObserver(this);
-  Shell::GetInstance()->system_tray_notifier()->
-      RemoveScreenCaptureObserver(this);
+  WmShell::Get()->system_tray_notifier()->RemoveScreenCaptureObserver(this);
 }
 
 views::View* ScreenCaptureTrayItem::CreateTrayView(LoginStatus status) {
   set_tray_view(
       new tray::ScreenTrayView(this, IDR_AURA_UBER_TRAY_SCREENSHARE));
   return tray_view();
 }
 
 views::View* ScreenCaptureTrayItem::CreateDefaultView(LoginStatus status) {
   set_default_view(new tray::ScreenStatusView(
@@ skipping 50 matching lines @@
   // screen capture is stopped externally.
   set_is_started(false);
   Update();
 }
 
 void ScreenCaptureTrayItem::OnCastingSessionStartedOrStopped(bool started) {
   is_casting_ = started;
 }
 
 }  // namespace ash