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

ash/wm/shelf_layout_manager_unittest.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/wm/shelf_layout_manager.h"
 
 #include "ash/accelerators/accelerator_controller.h"
 #include "ash/accelerators/accelerator_table.h"
 #include "ash/ash_switches.h"
 #include "ash/display/display_manager.h"
@@ skipping 62 matching lines @@
 
   bool changed_auto_hide_state_;
 
   DISALLOW_COPY_AND_ASSIGN(ShelfLayoutObserverTest);
 };
 
 // Trivial item implementation that tracks its views for testing.
 class TestItem : public SystemTrayItem {
  public:
   TestItem()
-      : tray_view_(NULL),
+      : SytemTrayItem(Shell::GetInstance()->system_tray()),
+        tray_view_(NULL),
         default_view_(NULL),
         detailed_view_(NULL),
         notification_view_(NULL) {}
 
   virtual views::View* CreateTrayView(user::LoginStatus status) OVERRIDE {
     tray_view_ = new views::View;
     // Add a label so it has non-zero width.
     tray_view_->SetLayoutManager(new views::FillLayout);
     tray_view_->AddChildView(new views::Label(UTF8ToUTF16("Tray")));
     return tray_view_;
@@ skipping 878 matching lines @@
       EXPECT_TRUE(status_area_widget->IsMessageBubbleShown());
     } else {
       EXPECT_FALSE(shelf->IsVisible());
       EXPECT_FALSE(status_area_widget->IsMessageBubbleShown());
     }
   }
 }
 
 }  // namespace internal
 }  // namespace ash