Revert of Remove InputMethodEventHandler.

ash/host/ash_window_tree_host_x11.h

 // 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.
 
 #ifndef ASH_HOST_ASH_WINDOW_TREE_HOST_X11_H_
 #define ASH_HOST_ASH_WINDOW_TREE_HOST_X11_H_
 
 #include <memory>
 
 #include "ash/ash_export.h"
@@ skipping 35 matching lines @@
 
   // aura::WindowTreeHostX11:
   void OnConfigureNotify() override;
   bool CanDispatchEvent(const ui::PlatformEvent& event) override;
   void TranslateAndDispatchLocatedEvent(ui::LocatedEvent* event) override;
 
   // EnvObserver overrides.
   void OnWindowInitialized(aura::Window* window) override;
   void OnHostInitialized(aura::WindowTreeHost* host) override;
 
+  // ui::internal::InputMethodDelegate:
+  ui::EventDispatchDetails DispatchKeyEventPostIME(
+      ui::KeyEvent* event) override;
+
   // Set the CrOS touchpad "tap paused" property. It is used to temporarily
   // turn off the Tap-to-click feature when the mouse pointer is invisible.
   void SetCrOSTapPaused(bool state);
 
   std::unique_ptr<XID[]> pointer_barriers_;
 
   TransformerHelper transformer_helper_;
 
   DISALLOW_COPY_AND_ASSIGN(AshWindowTreeHostX11);
 };
 
 }  // namespace ash
 
 #endif  // ASH_HOST_ASH_WINDOW_TREE_HOST_X11_H_