aura-x11: Make sure the list of devices to track are updated when device hierarchy changes.

ui/aura/root_window_host_linux.cc

 // Copyright (c) 2011 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/aura/root_window_host.h"
 
 #include <X11/cursorfont.h>
 #include <X11/Xlib.h>
 
 // Get rid of a macro from Xlib.h that conflicts with Aura's RootWindow class.
@@ skipping 326 matching lines @@
                     KeyPressMask | KeyReleaseMask |
                     EnterWindowMask | LeaveWindowMask |
                     ExposureMask | VisibilityChangeMask |
                     StructureNotifyMask | PropertyChangeMask |
                     PointerMotionMask;
   XSelectInput(xdisplay_, xwindow_, event_mask);
   XSelectInput(xdisplay_, x_root_window_, StructureNotifyMask);
   XFlush(xdisplay_);
 
   // TODO(sad): Re-enable once crbug.com/106516 is fixed.
-#if 0
   if (base::MessagePumpForUI::HasXInput2())
     ui::TouchFactory::GetInstance()->SetupXI2ForXWindow(xwindow_);
-#endif
 
   base::MessagePumpX::SetDefaultDispatcher(this);
   MessageLoopForUI::current()->AddDestructionObserver(this);
 }
 
 RootWindowHostLinux::~RootWindowHostLinux() {
   XDestroyWindow(xdisplay_, xwindow_);
 
   // Clears XCursorCache.
   ui::GetXCursor(ui::kCursorClearXCursorCache);
@@ skipping 54 matching lines @@
       if (size_changed)
         root_window_->OnHostResized(bounds.size());
       handled = true;
       break;
     }
     case GenericEvent: {
       ui::TouchFactory* factory = ui::TouchFactory::GetInstance();
       if (!factory->ShouldProcessXI2Event(xev))
         break;
 
+      // Update the device list if necessary.
+      if (xev->xgeneric.evtype == XI_HierarchyChanged) {
+        factory->UpdateDeviceList(xdisplay_);
+        handled = true;
+        break;
+      }
+
       // If this is a motion event we want to coalesce all pending motion
       // events that are at the top of the queue.
       XEvent last_event;
       int num_coalesced = 0;
       if (xev->xgeneric.evtype == XI_Motion) {
         num_coalesced = CoalescePendingXIMotionEvents(xev, &last_event);
         if (num_coalesced > 0)
           xev = &last_event;
       }
 
@@ skipping 195 matching lines @@
   return new RootWindowHostLinux(bounds);
 }
 
 // static
 gfx::Size RootWindowHost::GetNativeScreenSize() {
   ::Display* xdisplay = base::MessagePumpX::GetDefaultXDisplay();
   return gfx::Size(DisplayWidth(xdisplay, 0), DisplayHeight(xdisplay, 0));
 }
 
 }  // namespace aura