Add an adapter layer (WMHelper) between exo and ash.

components/exo/keyboard.cc

 // Copyright 2015 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 "components/exo/keyboard.h"
 
-#include "ash/shell.h"
 #include "components/exo/keyboard_delegate.h"
 #include "components/exo/shell_surface.h"
 #include "components/exo/surface.h"
 #include "ui/aura/client/focus_client.h"
 #include "ui/aura/window.h"
 #include "ui/base/ime/input_method.h"
 #include "ui/events/base_event_utils.h"
 #include "ui/events/event.h"
 #include "ui/views/widget/widget.h"
 
@@ skipping 49 matching lines @@
     }
   }
 
   return false;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // Keyboard, public:
 
 Keyboard::Keyboard(KeyboardDelegate* delegate) : delegate_(delegate) {
-  ash::Shell::GetInstance()->AddPostTargetHandler(this);
-  aura::client::FocusClient* focus_client =
-      aura::client::GetFocusClient(ash::Shell::GetPrimaryRootWindow());
-  focus_client->AddObserver(this);
-  OnWindowFocused(focus_client->GetFocusedWindow(), nullptr);
+  auto* helper = WMHelper::GetInstance();
+  helper->AddPostTargetHandler(this);
+  helper->AddFocusObserver(this);
+  OnWindowFocused(helper->GetFocusedWindow(), nullptr);
 }
 
 Keyboard::~Keyboard() {
   delegate_->OnKeyboardDestroying(this);
   if (focus_)
     focus_->RemoveSurfaceObserver(this);
-  aura::client::GetFocusClient(ash::Shell::GetPrimaryRootWindow())
-      ->RemoveObserver(this);
-  ash::Shell::GetInstance()->RemovePostTargetHandler(this);
+  auto* helper = WMHelper::GetInstance();
+  helper->RemoveFocusObserver(this);
+  helper->RemovePostTargetHandler(this);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // ui::EventHandler overrides:
 
 void Keyboard::OnKeyEvent(ui::KeyEvent* event) {
   // These modifiers reflect what Wayland is aware of.  For example,
   // EF_SCROLL_LOCK_ON is missing because Wayland doesn't support scroll lock.
   const int kModifierMask = ui::EF_SHIFT_DOWN | ui::EF_CONTROL_DOWN |
                             ui::EF_ALT_DOWN | ui::EF_COMMAND_DOWN |
@@ skipping 80 matching lines @@
     aura::Window* top_level_window = window->GetToplevelWindow();
     if (top_level_window)
       focus = ShellSurface::GetMainSurface(top_level_window);
   }
 
   return focus && delegate_->CanAcceptKeyboardEventsForSurface(focus) ? focus
                                                                       : nullptr;
 }
 
 }  // namespace exo