Don't track mouse events in HWNDMessageHandler when they are forwarded by the LegacyRenderWidgetHost

ui/views/controls/menu/menu_controller.cc

 // Copyright (c) 2012 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 "ui/views/controls/menu/menu_controller.h"
 
 #if defined(OS_WIN)
 #include <windowsx.h>
 #endif
 
@@ skipping 2112 matching lines @@
 
 void MenuController::RepostEvent(SubmenuView* source,
                                  const ui::LocatedEvent& event) {
   gfx::Point screen_loc(event.location());
   View::ConvertPointToScreen(source->GetScrollViewContainer(), &screen_loc);
 
   gfx::NativeView native_view = source->GetWidget()->GetNativeView();
   gfx::Screen* screen = gfx::Screen::GetScreenFor(native_view);
   gfx::NativeWindow window = screen->GetWindowAtScreenPoint(screen_loc);
 
-  if (!window)
-    return;
-
+  // On Windows, it is ok for window to be NULL. Please refer to the
+  // RepostLocatedEvent function for more information.
 #if defined(OS_WIN)
   // Release the capture.
   SubmenuView* submenu = state_.item->GetRootMenuItem()->GetSubmenu();
   submenu->ReleaseCapture();
 
   gfx::NativeView view = submenu->GetWidget()->GetNativeView();
-  if (view) {
+  if (view && window) {
     DWORD view_tid = GetWindowThreadProcessId(HWNDForNativeView(view), NULL);
     if (view_tid != GetWindowThreadProcessId(HWNDForNativeView(window), NULL)) {
       // Even though we have mouse capture, windows generates a mouse event if
       // the other window is in a separate thread. Only repost an event if
       // |view| was created on the same thread, else the target window can get
       // double events leading to bad behavior.
       return;
     }
   }
+#else
+  if (!window)
+    return;
 #endif
 
   scoped_ptr<ui::LocatedEvent> clone;
   if (event.IsMouseEvent()) {
     clone.reset(new ui::MouseEvent(static_cast<const ui::MouseEvent&>(event)));
   } else if (event.IsGestureEvent()) {
     // TODO(rbyers): Gesture event repost is tricky to get right
     // crbug.com/170987.
     return;
   } else {
@@ skipping 172 matching lines @@
              (!pending_state_.item->HasSubmenu() ||
               !pending_state_.item->GetSubmenu()->IsShowing())) {
     // On exit if the user hasn't selected an item with a submenu, move the
     // selection back to the parent menu item.
     SetSelection(pending_state_.item->GetParentMenuItem(),
                  SELECTION_OPEN_SUBMENU);
   }
 }
 
 }  // namespace views