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

ui/views/event_utils_aura.cc

 // Copyright 2013 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/event_utils.h"
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/aura/client/screen_position_client.h"
 #include "ui/aura/root_window.h"
 #include "ui/events/event.h"
 #include "ui/gfx/point.h"
 #include "ui/views/views_delegate.h"
 
 using aura::client::ScreenPositionClient;
 
 namespace views {
 
 bool RepostLocatedEvent(gfx::NativeWindow window,
                         const ui::LocatedEvent& event) {
+#if defined(OS_WIN)
+  // On Windows, if the |window| parameter is NULL, then we attempt to repost
+  // the event to the window at the current location, if it is on the current
+  // thread.
+  HWND target_window = NULL;
+  if (!window) {
+    target_window = ::WindowFromPoint(event.location().ToPOINT());
+    if (::GetWindowThreadProcessId(target_window, NULL) !=
+        ::GetCurrentThreadId())
+      return false;
+  } else {
+    if (ViewsDelegate::views_delegate &&
+        !ViewsDelegate::views_delegate->IsWindowInMetro(window))
+      target_window = window->GetDispatcher()->host()->GetAcceleratedWidget();
+  }
+  return RepostLocatedEventWin(target_window, event);
+#endif
   if (!window)
     return false;
 
-#if defined(OS_WIN)
-  if (ViewsDelegate::views_delegate &&
-      !ViewsDelegate::views_delegate->IsWindowInMetro(window)) {
-    return RepostLocatedEventWin(
-        window->GetDispatcher()->host()->GetAcceleratedWidget(), event);
-  }
-#endif
   aura::Window* root_window = window->GetRootWindow();
 
   gfx::Point root_loc(event.location());
   ScreenPositionClient* spc =
       aura::client::GetScreenPositionClient(root_window);
   if (!spc)
     return false;
 
   spc->ConvertPointFromScreen(root_window, &root_loc);
 
@@ skipping 10 matching lines @@
     return false;
   }
   relocated->set_location(root_loc);
   relocated->set_root_location(root_loc);
 
   root_window->GetDispatcher()->RepostEvent(*relocated);
   return true;
 }
 
 }  // namespace views