Make DispatchKeyEventPostIME() asynchronous.

chrome/browser/ui/views/ime_driver/remote_text_input_client.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.
 
 // Reduce number of log messages by logging each NOTIMPLEMENTED() only once.
 // This has to be before any other includes, else default is picked up.
 // See base/logging.h for details on this.
 #define NOTIMPLEMENTED_POLICY 5
 
 #include "chrome/browser/ui/views/ime_driver/remote_text_input_client.h"
@@ skipping 152 matching lines @@
   // TODO(moshayedi): crbug.com/631527.
   NOTIMPLEMENTED();
   return false;
 }
 
 void RemoteTextInputClient::SetTextEditCommandForNextKeyEvent(
     ui::TextEditCommand command) {
   // TODO(moshayedi): crbug.com/631527.
   NOTIMPLEMENTED();
 }
+
+ui::EventDispatchDetails RemoteTextInputClient::DispatchKeyEventPostIME(
+    ui::KeyEvent* event) {
+  return DispatchKeyEventPostIME(event, nullptr);
+}
+
+ui::EventDispatchDetails RemoteTextInputClient::DispatchKeyEventPostIME(
+    ui::KeyEvent* event,
+    std::unique_ptr<base::Callback<void(bool)>> ack_callback) {
+  pending_callbacks_.push_back(std::move(ack_callback));
+  remote_client_->DispatchKeyEventPostIME(
+      ui::Event::Clone(*event),
+      base::Bind(&RemoteTextInputClient::DispatchKeyEventPostIMECallback,
+                 base::Unretained(this)));
+  return ui::EventDispatchDetails();
+}
+
+void RemoteTextInputClient::DispatchKeyEventPostIMECallback(
+    bool stopped_propagation) {
+  DCHECK(!pending_callbacks_.empty());
+  std::unique_ptr<base::Callback<void(bool)>> ack_callback =
+      std::move(pending_callbacks_.front());
+  pending_callbacks_.pop_front();
+
+  if (ack_callback)
+    ack_callback->Run(stopped_propagation);
+}