Revert of Remove InputMethodEventHandler.

ash/host/ash_window_tree_host_platform.cc

 // Copyright 2016 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/host/ash_window_tree_host_platform.h"
 
 #include <utility>
 
 #include "ash/host/root_window_transformer.h"
 #include "ash/host/transformer_helper.h"
+#include "ash/ime/input_method_event_handler.h"
 #include "base/trace_event/trace_event.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_tree_host_platform.h"
 #include "ui/events/event_sink.h"
 #include "ui/events/null_event_targeter.h"
 #include "ui/gfx/geometry/insets.h"
 #include "ui/gfx/transform.h"
 #include "ui/platform_window/platform_window.h"
 
 #if defined(USE_OZONE)
@@ skipping 86 matching lines @@
   ConfineCursorToRootWindow();
 }
 
 void AshWindowTreeHostPlatform::DispatchEvent(ui::Event* event) {
   TRACE_EVENT0("input", "AshWindowTreeHostPlatform::DispatchEvent");
   if (event->IsLocatedEvent())
     TranslateLocatedEvent(static_cast<ui::LocatedEvent*>(event));
   SendEventToSink(event);
 }
 
+ui::EventDispatchDetails AshWindowTreeHostPlatform::DispatchKeyEventPostIME(
+    ui::KeyEvent* event) {
+  input_method_handler()->SetPostIME(true);
+  ui::EventDispatchDetails details = event_sink()->OnEventFromSource(event);
+  if (!details.dispatcher_destroyed)
+    input_method_handler()->SetPostIME(false);
+  return details;
+}
+
 void AshWindowTreeHostPlatform::SetTapToClickPaused(bool state) {
 #if defined(USE_OZONE)
   DCHECK(ui::OzonePlatform::GetInstance()->GetInputController());
 
   // Temporarily pause tap-to-click when the cursor is hidden.
   ui::OzonePlatform::GetInstance()->GetInputController()->SetTapToClickPaused(
       state);
 #endif
 }
 
 }  // namespace ash