Stop using shell::GetInstance()->system_tray() in system tray items

ash/system/tray_accessibility.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/system/tray_accessibility.h"
 
 #include "ash/shell.h"
 #include "ash/shell_delegate.h"
 #include "ash/system/tray/tray_constants.h"
 #include "ash/system/tray/tray_views.h"
@@ skipping 39 matching lines @@
       Shell::GetInstance()->delegate()->ToggleSpokenFeedback();
     GetWidget()->Close();
     return true;
   }
 
  private:
 
   DISALLOW_COPY_AND_ASSIGN(DefaultAccessibilityView);
 };
 
-TrayAccessibility::TrayAccessibility()
-    : TrayImageItem(IDR_AURA_UBER_TRAY_ACCESSIBILITY),
+TrayAccessibility::TrayAccessibility(SystemTray* system_tray)
+    : TrayImageItem(system_tray, IDR_AURA_UBER_TRAY_ACCESSIBILITY),
       default_(NULL),
       detailed_(NULL) {
 }
 
 TrayAccessibility::~TrayAccessibility() {}
 
 bool TrayAccessibility::GetInitialVisibility() {
   return Shell::GetInstance()->delegate() &&
       Shell::GetInstance()->delegate()->IsSpokenFeedbackEnabled();
 }
@@ skipping 42 matching lines @@
 
   if (enabled) {
     PopupDetailedView(kTrayPopupAutoCloseDelayForTextInSeconds, false);
   } else if (detailed_) {
     detailed_->GetWidget()->Close();
   }
 }
 
 }  // namespace internal
 }  // namespace ash