Enable MSVC warning for unused locals.

ash/root_window_controller_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/root_window_controller.h"
 
 #include "ash/session/session_state_delegate.h"
 #include "ash/shelf/shelf_layout_manager.h"
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
@@ skipping 358 matching lines @@
   views::Widget* session_modal_widget =
         CreateModalWidget(gfx::Rect(300, 10, 100, 100));
   EXPECT_EQ(controller->GetContainer(kShellWindowId_SystemModalContainer)
                 ->layout_manager(),
             controller->GetSystemModalLayoutManager(
                 session_modal_widget->GetNativeView()));
 }
 
 TEST_F(RootWindowControllerTest, ModalContainerBlockedSession) {
   UpdateDisplay("600x600");
-  Shell* shell = Shell::GetInstance();
-  RootWindowController* controller = shell->GetPrimaryRootWindowController();
+  RootWindowController* controller = Shell::GetPrimaryRootWindowController();
   aura::Window* lock_container =
       controller->GetContainer(kShellWindowId_LockScreenContainer);
   for (int block_reason = FIRST_BLOCK_REASON;
        block_reason < NUMBER_OF_BLOCK_REASONS;
        ++block_reason) {
     views::Widget* session_modal_widget =
           CreateModalWidget(gfx::Rect(300, 10, 100, 100));
     EXPECT_EQ(controller->GetContainer(kShellWindowId_SystemModalContainer)
                   ->layout_manager(),
               controller->GetSystemModalLayoutManager(
@@ skipping 564 matching lines @@
   ASSERT_TRUE(keyboard_container);
   keyboard_container->Show();
   EXPECT_EQ("0,0 800x600", keyboard_container->bounds().ToString());
 
   UpdateDisplay("600x800");
   EXPECT_EQ("0,0 600x800", keyboard_container->bounds().ToString());
 }
 
 }  // namespace test
 }  // namespace ash