Make Combobox portable

views/controls/native_control_win.cc

 // Copyright (c) 2009 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 "views/controls/native_control_win.h"
 
 #include "app/l10n_util_win.h"
 #include "base/logging.h"
 #include "base/win_util.h"
 
@@ skipping 96 matching lines @@
     x = point.x();
     y = point.y();
     is_mouse = false;
   }
   View::ShowContextMenu(x, y, is_mouse);
 }
 
 void NativeControlWin::NativeControlCreated(HWND native_control) {
   // Associate this object with the control's HWND so that WidgetWin can find
   // this object when it receives messages from it.
+  // Note that we never unset this property. We don't have to.
   SetProp(native_control, kNativeControlWinKey, this);
 
-  // Subclass the window so we can monitor for key presses.
-  original_wndproc_ =
-      win_util::SetWindowProc(native_control,
-                              &NativeControlWin::NativeControlWndProc);
-  SetProp(native_control, kNativeControlOriginalWndProcKey, original_wndproc_);
+  // Subclass the window so we can monitor for key presses. It's important that
+  // we *only* do this if the derived class wants to intercept keypresses,
+  // because otherwise the subclass can mysteriously interfere with certain
+  // other controls, like the combobox, and cause weird effects.
+  if (NotifyOnKeyDown()) {
+    original_wndproc_ =
+        win_util::SetWindowProc(native_control,
+                                &NativeControlWin::NativeControlWndProc);
+    SetProp(native_control, kNativeControlOriginalWndProcKey,
+            original_wndproc_);
+  }
 
   Attach(native_control);
   // native_view() is now valid.
 
   // Update the newly created HWND with any resident enabled state.
   EnableWindow(native_view(), IsEnabled());
 
   // This message ensures that the focus border is shown.
   SendMessage(native_view(), WM_CHANGEUISTATE,
               MAKEWPARAM(UIS_CLEAR, UISF_HIDEFOCUS), 0);
@@ skipping 47 matching lines @@
                                                LPARAM l_param) {
   NativeControlWin* native_control =
       static_cast<NativeControlWin*>(GetProp(window, kNativeControlWinKey));
   DCHECK(native_control);
 
   if (message == WM_KEYDOWN && native_control->NotifyOnKeyDown()) {
     if (native_control->OnKeyDown(static_cast<int>(w_param)))
       return 0;
   } else if (message == WM_DESTROY) {
     win_util::SetWindowProc(window, native_control->original_wndproc_);
-    RemoveProp(window, kNativeControlWinKey);
   }
 
   return CallWindowProc(native_control->original_wndproc_, window, message,
                         w_param, l_param);
 }
 
 }  // namespace views