Revert of chromeos: Makes mushrome use simplified display management

ui/aura/window_tree_host.h

 // 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.
 
 #ifndef UI_AURA_WINDOW_TREE_HOST_H_
 #define UI_AURA_WINDOW_TREE_HOST_H_
 
 #include <memory>
 #include <vector>
 
@@ skipping 115 matching lines @@
   // Moves the cursor to the specified location relative to the root window.
   void MoveCursorToLocationInDIP(const gfx::Point& location_in_dip);
 
   // Moves the cursor to the |location_in_pixels| given in host coordinates.
   void MoveCursorToLocationInPixels(const gfx::Point& location_in_pixels);
 
   gfx::NativeCursor last_cursor() const { return last_cursor_; }
 
   // Gets the InputMethod instance, if NULL, creates & owns it.
   ui::InputMethod* GetInputMethod();
-  bool has_input_method() const { return input_method_ != nullptr; }
 
   // Sets a shared unowned InputMethod. This is used when there is a singleton
   // InputMethod shared between multiple WindowTreeHost instances.
   //
   // This is used for Ash only. There are 2 reasons:
   // 1) ChromeOS virtual keyboard needs to receive ShowImeIfNeeded notification
   // from InputMethod. Multiple InputMethod instances makes it hard to
   // register/unregister the observer for that notification.
   // 2) For Ozone, there is no native focus state for the root window and
   // WindowTreeHost. See DrmWindowHost::CanDispatchEvent, the key events always
@@ skipping 119 matching lines @@
   bool owned_input_method_;
 
   gfx::Insets output_surface_padding_in_pixels_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowTreeHost);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_WINDOW_TREE_HOST_H_