Avoids releasing capture prematurily when dragging tabs from one to another browser window

ui/views/widget/desktop_aura/x11_desktop_handler.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/widget/desktop_aura/x11_desktop_handler.h"
 
 #include <X11/Xatom.h>
 #include <X11/Xlib.h>
 
 #include "base/message_loop/message_loop.h"
@@ skipping 74 matching lines @@
     XSendEvent(xdisplay_, x_root_window_, False,
                SubstructureRedirectMask | SubstructureNotifyMask,
                &xclient);
   } else {
     XRaiseWindow(xdisplay_, window);
 
     // XRaiseWindow will not give input focus to the window. We now need to ask
     // the X server to do that. Note that the call will raise an X error if the
     // window is not mapped.
     XSetInputFocus(xdisplay_, window, RevertToParent, CurrentTime);
-
-    OnActiveWindowChanged(window);
   }
+  // Notify synchronously in order to maintain focus on a correct view when
+  // activation changes.
+  OnActiveWindowChanged(window);

[varkha, 2014/02/26 20:30:18]

Without this when a tab that is dragged from one browser to another has focus in
a text field that focus gets lost after the drag. Calling it synchronously helps
and focus is maintained (avoiding symptoms from http://crbug.com/275329. Is
there a better way?

[Elliot Glaysher, 2014/02/26 20:33:17]

Not that I know of. sadrul@ might be a better person to ask though, since he has
more in depth knowledge of X11 lore.

 }
 
 void X11DesktopHandler::DeactivateWindow(::Window window) {
   DCHECK(IsActiveWindow(window));
 
   std::vector< ::Window > windows;
   if (!ui::GetXWindowStack(x_root_window_, &windows)) {
     // TODO(mlamouri): use XQueryTree in case of _NET_CLIENT_LIST_STACKING is
     // not supported by the WM.
     NOTIMPLEMENTED();
@@ skipping 122 matching lines @@
     return *it;
   }
 
   // If we reached that point, that means we have not found an appropriate
   // window to activate. There is nothing we can do about it and the caller
   // should take care of doing the right thing.
   return 0;
 }
 
 }  // namespace views