Revert of Adding split view divider widget.

athena/wm/window_manager_impl.cc

 // Copyright 2014 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 "athena/wm/window_manager_impl.h"
 
 #include <algorithm>
 
 #include "athena/screen/public/screen_manager.h"
 #include "athena/util/container_priorities.h"
@@ skipping 131 matching lines @@
 WindowManagerImpl::WindowManagerImpl() {
   ScreenManager::ContainerParams params("DefaultContainer", CP_DEFAULT);
   params.can_activate_children = true;
   container_.reset(ScreenManager::Get()->CreateDefaultContainer(params));
   container_->SetLayoutManager(new AthenaContainerLayoutManager);
   container_->AddObserver(this);
   window_list_provider_.reset(new WindowListProviderImpl(container_.get()));
   bezel_controller_.reset(new BezelController(container_.get()));
   split_view_controller_.reset(
       new SplitViewController(container_.get(), window_list_provider_.get()));
-  AddObserver(split_view_controller_.get());
   bezel_controller_->set_left_right_delegate(split_view_controller_.get());
   container_->AddPreTargetHandler(bezel_controller_.get());
   title_drag_controller_.reset(new TitleDragController(container_.get(), this));
   wm_state_.reset(new wm::WMState());
   aura::client::ActivationClient* activation_client =
       aura::client::GetActivationClient(container_->GetRootWindow());
   shadow_controller_.reset(new wm::ShadowController(activation_client));
   instance = this;
   InstallAccelerators();
 }
 
 WindowManagerImpl::~WindowManagerImpl() {
   overview_.reset();
-  RemoveObserver(split_view_controller_.get());
   split_view_controller_.reset();
   window_list_provider_.reset();
   if (container_) {
     container_->RemoveObserver(this);
     container_->RemovePreTargetHandler(bezel_controller_.get());
   }
   // |title_drag_controller_| needs to be reset before |container_|.
   title_drag_controller_.reset();
   container_.reset();
   instance = NULL;
@@ skipping 250 matching lines @@
   DCHECK(!instance);
 }
 
 // static
 WindowManager* WindowManager::GetInstance() {
   DCHECK(instance);
   return instance;
 }
 
 }  // namespace athena