Introduce empty IBusDaemonController class.

chromeos/ime/ibus_daemon_controller.cc

+// 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.
+
+#include "chromeos/ime/ibus_daemon_controller.h"
+
+#include "base/chromeos/chromeos_version.h"
+
+namespace chromeos {
+
+namespace {
+
+IBusDaemonController* g_ibus_daemon_controller = NULL;
+
+// The implementation of IBusDaemonController.
+class IBusDaemonControllerImpl : public IBusDaemonController {

[satorux1, 2013/01/22 07:06:01]

This class should be used from a single thread, right? You could use
ThreadChecker in base/threading.

[Seigo Nonaka, 2013/01/22 10:53:48]

Right, use NonThreadSafe for thread checking.
On 2013/01/22 07:06:01, satorux1 wrote:

[satorux1, 2013/01/22 17:09:52]

I'd suggest to use ThreadChecker. non_thread_safe.h says:

// Note that base::ThreadChecker offers identical functionality to              
         
// NonThreadSafe, but does not require inheritence. In general, it is preferable
         
// to have a base::ThreadChecker as a member, rather than inherit from          
         
// NonThreadSafe. For more details about when to choose one over the other, see 
         
// the documentation for base::ThreadChecker.                                   
         


In general, composition is more preferable than inheritance. Inheritance is
harder to follow.

[Seigo Nonaka, 2013/01/23 08:06:08]

Sorry I missed NonThreadSafe comment.
Updated patch to use ThreadChecker.
Thank you!

+ public:
+  IBusDaemonControllerImpl() {}
+
+  ~IBusDaemonControllerImpl() {}
+
+  // IBusDaemonController override:
+  void Initialize(
+      const scoped_refptr<base::SequencedTaskRunner>& ui_task_runner,
+      const scoped_refptr<base::SequencedTaskRunner>& file_task_runner) {
+    // TODO(nona): Implement this.
+  }
+
+  // IBusDaemonController override:
+  void AddObserver(Observer* observer) {
+    // TODO(nona): Implement this.
+  }
+
+  // IBusDaemonController override:
+  void RemoveObserver(Observer* observer) {
+    // TODO(nona): Implement this.
+  }
+
+  // IBusDaemonController override:
+  bool Start() OVERRIDE {
+    // TODO(nona): Implement this.
+    return true;
+  }
+
+  // IBusDaemonController override:
+  bool Stop() OVERRIDE {
+    // TODO(nona): Implement this.
+    return true;
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(IBusDaemonControllerImpl);
+};
+
+// The stub implementation of IBusDaemonController.
+class IBusDaemonControllerStubImpl : public IBusDaemonController {
+ public:
+  IBusDaemonControllerStubImpl() {}
+  virtual ~IBusDaemonControllerStubImpl() {}
+
+  // IBusDaemonController overrides:
+  void Initialize(
+      const scoped_refptr<base::SequencedTaskRunner>& ui_runner,
+      const scoped_refptr<base::SequencedTaskRunner>& file_runner) OVERRIDE {}
+  virtual void AddObserver(Observer* observer) OVERRIDE {}
+  virtual void RemoveObserver(Observer* observer) OVERRIDE {}
+  virtual bool Start() OVERRIDE { return true; }
+  virtual bool Stop() OVERRIDE { return true; }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(IBusDaemonControllerStubImpl);
+};
+
+}  // namespace
+
+///////////////////////////////////////////////////////////////////////////////
+// IBusDaemonController
+
+IBusDaemonController::IBusDaemonController() {
+}
+
+IBusDaemonController::~IBusDaemonController() {
+}
+
+IBusDaemonController* IBusDaemonController::GetInstance() {
+  if (!g_ibus_daemon_controller) {
+    if (base::chromeos::IsRunningOnChromeOS()) {
+      g_ibus_daemon_controller = new IBusDaemonControllerImpl();
+    } else {
+      g_ibus_daemon_controller = new IBusDaemonControllerStubImpl();
+    }
+  }
+  return g_ibus_daemon_controller;
+}
+
+}  // namespace chromeos