Adds the ability for classes other than native control to process

views/widget/child_window_message_processor.h

+// Copyright (c) 2010 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 VIEWS_WIDGET_CHILD_WINDOW_MESSAGE_PROCESSOR_H_
+#define VIEWS_WIDGET_CHILD_WINDOW_MESSAGE_PROCESSOR_H_
+#pragma once
+
+#include <windows.h>
+
+namespace app {
+namespace win {
+class ScopedProp;
+}
+}
+
+namespace views {
+
+// Windows sends a handful of messages to the parent window rather than the
+// window itself. For example, selection changes of a rich edit (EN_SELCHANGE)
+// are sent to the parent, not the window. Typically such message are best
+// dealt with by the window rather than the parent. WidgetWin allows for
+// registering a ChildWindowMessageProcessor to handle such messages.
+class ChildWindowMessageProcessor {
+ public:
+  // Registers |processor| for |hwnd|. The caller takes ownership of the
+  // returned object.
+  static app::win::ScopedProp* Register(HWND hwnd,
+                                        ChildWindowMessageProcessor* processor);
+
+  // Returns the ChildWindowMessageProcessor for |hwnd|, NULL if there isn't
+  // one.
+  static ChildWindowMessageProcessor* Get(HWND hwnd);
+
+  // Invoked for any messages that are sent to the parent and originated from
+  // the HWND this ChildWindowMessageProcessor was registered for. Returns true
+  // if the message was handled with a valid result in |result|. Returns false
+  // if the message was not handled.
+  virtual bool ProcessMessage(UINT message,
+                              WPARAM w_param,
+                              LPARAM l_param,
+                              LRESULT* result) = 0;
+
+ protected:
+  virtual ~ChildWindowMessageProcessor() {}
+};
+
+}  // namespace views
+
+#endif // VIEWS_WIDGET_CHILD_WINDOW_MESSAGE_PROCESSOR_H_