Make File-Picker modal on Linux

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 152 matching lines @@
 uint32_t X11DesktopHandler::DispatchEvent(const ui::PlatformEvent& event) {
   switch (event->type) {
     case PropertyNotify: {
       // Check for a change to the active window.
       CHECK_EQ(x_root_window_, event->xproperty.window);
       ::Atom active_window_atom = atom_cache_.GetAtom("_NET_ACTIVE_WINDOW");
       if (event->xproperty.atom == active_window_atom) {
         ::Window window;
         if (ui::GetXIDProperty(x_root_window_, "_NET_ACTIVE_WINDOW", &window) &&
             window) {
+          // Set focus to the modal dialog instead of the host window.
+          DesktopWindowTreeHostX11* new_host =
+              views::DesktopWindowTreeHostX11::GetHostForXID(window);
+          if (new_host && new_host->GetModalDialog()) {
+            XSetInputFocus(xdisplay_, new_host->GetModalDialog(),
+                RevertToParent, CurrentTime);
+            break;
+          }
+
           OnActiveWindowChanged(window, ACTIVE);
         }
       }
       break;
     }
 
     case CreateNotify:
       OnWindowCreatedOrDestroyed(event->type, event->xcreatewindow.window);
       break;
     case DestroyNotify:
@@ skipping 56 matching lines @@
     ui::XMenuList::GetInstance()->MaybeUnregisterMenu(window);
   }
 
   if (event_type == DestroyNotify) {
     // Notify the XForeignWindowManager that |window| has been destroyed.
     ui::XForeignWindowManager::GetInstance()->OnWindowDestroyed(window);
   }
 }
 
 }  // namespace views