Rewrite scoped_ptr<T>(NULL) to use the default ctor in ash/.

ash/wm/workspace/workspace_cycler.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/workspace/workspace_cycler.h"
 
 #include <cmath>
 
 #include "ash/session_state_delegate.h"
 #include "ash/shell.h"
@@ skipping 13 matching lines @@
 bool IsCyclingAllowed() {
   // Cycling is disabled if the screen is locked or a modal dialog is open.
   return !Shell::GetInstance()->session_state_delegate()->IsScreenLocked() &&
          !Shell::GetInstance()->IsSystemModalWindowOpen();
 }
 
 }  // namespace
 
 WorkspaceCycler::WorkspaceCycler(WorkspaceManager* workspace_manager)
     : workspace_manager_(workspace_manager),
-      animator_(NULL),
       state_(NOT_CYCLING),
       scroll_x_(0.0f),
       scroll_y_(0.0f) {
   ash::Shell::GetInstance()->AddPreTargetHandler(this);
 }
 
 WorkspaceCycler::~WorkspaceCycler() {
   SetState(NOT_CYCLING);
   ash::Shell::GetInstance()->RemovePreTargetHandler(this);
 }
@@ skipping 126 matching lines @@
   animator_.reset();
   SetState(NOT_CYCLING);
 
   // Activate the workspace after updating the state so that a call to
   // AbortCycling() as a result of SetActiveWorkspaceFromCycler() is a noop.
   workspace_manager_->SetActiveWorkspaceFromCycler(workspace_to_activate);
 }
 
 }  // namespace internal
 }  // namespace ash