Add MessageHandlerDelegate

atom/browser/ui/win/message_handler_delegate.h

@@ -0,0 +1,26 @@
+// Copyright (c) 2015 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#ifndef ATOM_BROWSER_UI_WIN_MESSAGE_HANDLER_DELEGATE_H_
+#define ATOM_BROWSER_UI_WIN_MESSAGE_HANDLER_DELEGATE_H_
+
+#include <windows.h>
+
+namespace atom {
+
+class MessageHandlerDelegate {
+ public:
+  // Catch-all message handling and filtering. Called before
+  // HWNDMessageHandler's built-in handling, which may pre-empt some
+  // expectations in Views/Aura if messages are consumed. Returns true if the
+  // message was consumed by the delegate and should not be processed further
+  // by the HWNDMessageHandler. In this case, |result| is returned. |result| is
+  // not modified otherwise.
+  virtual bool PreHandleMSG(
+      UINT message, WPARAM w_param, LPARAM l_param, LRESULT* result);
+};
+
+}  // namespace atom
+
+#endif  // ATOM_BROWSER_UI_WIN_MESSAGE_HANDLER_DELEGATE_H_