Moved code implementing message-only windows to a dedicated class (Windows only).

remoting/host/win/message_window.h

+// Copyright 2013 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 REMOTING_HOST_WIN_MESSAGE_WINDOW_H_
+#define REMOTING_HOST_WIN_MESSAGE_WINDOW_H_
+
+#include <windows.h>
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "base/threading/non_thread_safe.h"
+
+namespace remoting {
+namespace win {
+
+// Implements a message-only window.
+class MessageWindow : base::NonThreadSafe {
+ public:
+  // Handles incoming window messages.
+  class Delegate {
+   public:
+    virtual ~Delegate() {}
+
+    virtual bool HandleMessage(UINT message, WPARAM wparam, LPARAM lparam,
+                               LRESULT* result) = 0;
+  };
+
+  MessageWindow();
+  MessageWindow(const std::string& class_name, HINSTANCE instance);
+  ~MessageWindow();
+
+  // Registers the window class and creates the window. The incoming messages
+  // will be handled by |delegate|. |delegate| must outlive |this|.
+  bool Create(Delegate* delegate);
+
+  HWND hwnd() const { return window_; }
+
+ private:
+  // Invoked by the OS to process incoming window messages.
+  static LRESULT CALLBACK WindowProc(HWND hwnd, UINT message, WPARAM wparam,
+                                     LPARAM lparam);
+
+  // Atom representing the registered window class.
+  ATOM atom_;
+
+  // MessageWindow class name.
+  std::string class_name_;
+
+  // Instance of the module containing the window procedure.
+  HINSTANCE instance_;
+
+  // Handle of the input window.
+  HWND window_;
+
+  DISALLOW_COPY_AND_ASSIGN(MessageWindow);
+};
+
+}  // namespace win
+}  // namespace remoting
+
+#endif  // REMOTING_HOST_WIN_MESSAGE_WINDOW_H_