Revert of Remove InputMethodEventHandler.

ash/mus/ash_window_tree_host_mus.cc

 // Copyright 2017 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/mus/ash_window_tree_host_mus.h"
 
 #include "ash/host/root_window_transformer.h"
 #include "ash/host/transformer_helper.h"
+#include "ash/ime/input_method_event_handler.h"
 #include "base/memory/ptr_util.h"
 #include "ui/aura/mus/window_tree_host_mus_init_params.h"
 #include "ui/aura/window.h"
 #include "ui/events/event_sink.h"
 #include "ui/events/null_event_targeter.h"
 
 namespace ash {
 
 AshWindowTreeHostMus::AshWindowTreeHostMus(
     aura::WindowTreeHostMusInitParams init_params)
@@ skipping 59 matching lines @@
 
 gfx::Transform AshWindowTreeHostMus::GetInverseRootTransform() const {
   return transformer_helper_->GetInverseTransform();
 }
 
 void AshWindowTreeHostMus::UpdateRootWindowSizeInPixels(
     const gfx::Size& host_size_in_pixels) {
   transformer_helper_->UpdateWindowSize(host_size_in_pixels);
 }
 
+ui::EventDispatchDetails AshWindowTreeHostMus::DispatchKeyEventPostIME(
+    ui::KeyEvent* event) {
+  // input_method_handler() can be null when using IME service with --mus.
+  if (input_method_handler())
+    input_method_handler()->SetPostIME(true);
+  ui::EventDispatchDetails details = SendEventToSink(event);
+  if (input_method_handler() && !details.dispatcher_destroyed)
+    input_method_handler()->SetPostIME(false);
+  return details;
+}
+
 }  // namespace ash