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 29 matching lines @@
   return g_handler;
 }
 
 X11DesktopHandler::X11DesktopHandler()
     : xdisplay_(gfx::GetXDisplay()),
       x_root_window_(DefaultRootWindow(xdisplay_)),
       wm_user_time_ms_(0),
       current_window_(None),
       current_window_active_state_(NOT_ACTIVE),
       atom_cache_(xdisplay_, kAtomsToCache),
-      wm_supports_active_window_(false) {
+      wm_supports_active_window_(false),
+      modal_dialog_xid_(None) {
   if (ui::PlatformEventSource::GetInstance())
     ui::PlatformEventSource::GetInstance()->AddPlatformEventDispatcher(this);
   aura::Env::GetInstance()->AddObserver(this);
 
   XWindowAttributes attr;
   XGetWindowAttributes(xdisplay_, x_root_window_, &attr);
   XSelectInput(xdisplay_, x_root_window_,
                attr.your_event_mask | PropertyChangeMask |
                StructureNotifyMask | SubstructureNotifyMask);
 
@@ skipping 102 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.
+          if (modal_dialog_xid_) {
+             XSetInputFocus(xdisplay_, modal_dialog_xid_, RevertToParent,
+                 CurrentTime);

[sadrul, 2015/06/30 17:30:56]

Is it necessary to maintain a separate modal_dialog_xid_ here? Can you not query
the DWTHX11 here instead?

[joone, 2015/07/01 03:16:06]

Yes, we can query the DWTHX11.

+             break;
+          }
+
           OnActiveWindowChanged(window, ACTIVE);
         }
       }
       break;
     }
 
     case CreateNotify:
       OnWindowCreatedOrDestroyed(event->type, event->xcreatewindow.window);
       break;
     case DestroyNotify:
@@ skipping 26 matching lines @@
       old_host->HandleNativeWidgetActivationChanged(false);
   }
 
   // Update the current window ID to effectively change the active widget.
   current_window_ = xid;
   current_window_active_state_ = active_state;
 
   if (active_state == ACTIVE) {
     DesktopWindowTreeHostX11* new_host =
         views::DesktopWindowTreeHostX11::GetHostForXID(xid);
-    if (new_host)
+    if (new_host) {
       new_host->HandleNativeWidgetActivationChanged(true);
+      modal_dialog_xid_ = new_host->GetModalDialog();

[sadrul, 2015/06/30 17:30:56]

Should you set the input-focus here instead?

[joone, 2015/07/01 03:16:06]

The file dialog doesn't pop-up well when opening two browser windows.

[sadrul, 2015/07/01 03:58:14]

Can you clarify what you mean? It should be OK to have two browser windows, open
a modal dialog for one of them, and then switch between the other browser
window, and this modal+browser window, right? So shouldn't we want to make sure
the other browser window does get deactivated correctly (ie. run the code in
lines 213:218 above to deactivate the other browser window, and then instead of
activating this browser window, set input-focus to the modal dialog)?

[joone, 2015/07/01 21:40:37]

Yes, each window can have its own modal dialog and they(window or window+modal
dialog) can be switched among each other.
Now, it is okay to set the input-focus here. There might have been a mistake to
test this fix.

+    }
   }
 }
 
 void X11DesktopHandler::OnWindowCreatedOrDestroyed(int event_type,
                                                    XID window) {
   // Menus created by Chrome can be drag and drop targets. Since they are
   // direct children of the screen root window and have override_redirect
   // we cannot use regular _NET_CLIENT_LIST_STACKING property to find them
   // and use a separate cache to keep track of them.
   // TODO(varkha): Implement caching of all top level X windows and their
   // coordinates and stacking order to eliminate repeated calls to the X server
   // during mouse movement, drag and shaping events.
   if (event_type == CreateNotify) {
     // The window might be destroyed if the message pump did not get a chance to
     // run but we can safely ignore the X error.
     gfx::X11ErrorTracker error_tracker;
     ui::XMenuList::GetInstance()->MaybeRegisterMenu(window);
   } else {
     ui::XMenuList::GetInstance()->MaybeUnregisterMenu(window);
   }
 
   if (event_type == DestroyNotify) {
     // Notify the XForeignWindowManager that |window| has been destroyed.
     ui::XForeignWindowManager::GetInstance()->OnWindowDestroyed(window);
   }
 }
 
 }  // namespace views