Add MessageHandlerDelegate

atom/browser/ui/win/atom_desktop_window_tree_host_win.cc

@@ -12,10 +12,12 @@
 namespace atom {
 
 AtomDesktopWindowTreeHostWin::AtomDesktopWindowTreeHostWin(
+    MessageHandlerDelegate* delegate,
     views::internal::NativeWidgetDelegate* native_widget_delegate,
     views::DesktopNativeWidgetAura* desktop_native_widget_aura)
         : views::DesktopWindowTreeHostWin(native_widget_delegate,
-                                          desktop_native_widget_aura) {
+                                          desktop_native_widget_aura),
+          delegate_(delegate) {
 }
 
 AtomDesktopWindowTreeHostWin::~AtomDesktopWindowTreeHostWin() {

atom/browser/ui/win/atom_desktop_window_tree_host_win.h

@@ -16,25 +16,30 @@
 
 namespace atom {
 
+class MessageHandlerDelegate;
+
 class AtomDesktopWindowTreeHostWin : public views::DesktopWindowTreeHostWin {
  public:
   AtomDesktopWindowTreeHostWin(
+      MessageHandlerDelegate* delegate,
       views::internal::NativeWidgetDelegate* native_widget_delegate,
       views::DesktopNativeWidgetAura* desktop_native_widget_aura);
-  ~AtomDesktopWindowTreeHostWin();
+  ~AtomDesktopWindowTreeHostWin() override;
 
   bool SetThumbarButtons(
       HWND window,
       const std::vector<NativeWindow::ThumbarButton>& buttons);
 
  protected:
-  bool PreHandleMSG(UINT message,
-                    WPARAM w_param,
-                    LPARAM l_param,
-                    LRESULT* result) override;
+  bool PreHandleMSG(
+      UINT message, WPARAM w_param, LPARAM l_param, LRESULT* result) override;
 
  private:
+  MessageHandlerDelegate* delegate_;  // weak ref
+
   scoped_ptr<ThumbarHost> thumbar_host_;
+
+  DISALLOW_COPY_AND_ASSIGN(AtomDesktopWindowTreeHostWin);
 };
 
 }  // namespace atom

atom/browser/ui/win/message_handler_delegate.cc

@@ -0,0 +1,14 @@
+// Copyright (c) 2015 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#include "atom/browser/ui/win/message_handler_delegate.h"
+
+namespace atom {
+
+bool MessageHandlerDelegate::PreHandleMSG(
+    UINT message, WPARAM w_param, LPARAM l_param, LRESULT* result) {
+  return false;
+}
+
+}  // namespace atom

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_