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

ash/system/tray/tray_item_more.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/tray_item_more.h"
 
 #include "ash/system/tray/system_tray_item.h"
 #include "ash/system/tray/tray_constants.h"
 #include "ash/system/tray/tray_views.h"
 #include "grit/ash_resources.h"
@@ skipping 52 matching lines @@
 void TrayItemMore::ReplaceIcon(views::View* view) {
   delete icon_;
   icon_ = NULL;
   AddChildViewAt(view, 0);
 }
 
 bool TrayItemMore::PerformAction(const ui::Event& event) {
   if (!show_more_)
     return false;
 
-  owner_->TransitionDetailedView();
+  owner()->TransitionDetailedView();
   return true;
 }
 
 void TrayItemMore::Layout() {
   // Let the box-layout do the layout first. Then move the '>' arrow to right
   // align.
   views::View::Layout();
 
   if (!show_more_)
     return;
@@ skipping 13 matching lines @@
   }
 }
 
 void TrayItemMore::GetAccessibleState(ui::AccessibleViewState* state) {
   state->role = ui::AccessibilityTypes::ROLE_PUSHBUTTON;
   state->name = accessible_name_;
 }
 
 }  // namespace internal
 }  // namespace ash