Remove the seemlingly uncecessary AddPreTargetHandler

ash/shell.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/shell.h"
 
 #include <algorithm>
 #include <string>
 
 #include "ash/accelerators/accelerator_controller.h"
@@ skipping 844 matching lines @@
 
   aura::Env::CreateInstance(true);
   aura::Env::GetInstance()->set_context_factory(init_params.context_factory);
 
   // The WindowModalityController needs to be at the front of the input event
   // pretarget handler list to ensure that it processes input events when modal
   // windows are active.
   window_modality_controller_.reset(
       new ::wm::WindowModalityController(this));
 
-  AddPreTargetHandler(this);
-
   env_filter_.reset(new ::wm::CompoundEventFilter);
   AddPreTargetHandler(env_filter_.get());
 
   ::wm::FocusController* focus_controller =
       new ::wm::FocusController(new wm::AshFocusRules);
   focus_client_.reset(focus_controller);
   activation_client_ = focus_controller;
   activation_client_->AddObserver(this);
   focus_cycler_.reset(new FocusCycler());
 
@@ skipping 276 matching lines @@
 ////////////////////////////////////////////////////////////////////////////////
 // Shell, aura::client::ActivationChangeObserver implementation:
 
 void Shell::OnWindowActivated(aura::Window* gained_active,
                               aura::Window* lost_active) {
   if (gained_active)
     target_root_window_ = gained_active->GetRootWindow();
 }
 
 }  // namespace ash