Update DesktopScreenX11::displays_ when the display layout changes

ui/views/widget/desktop_aura/desktop_screen_x11.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/desktop_screen_x11.h"
 
 #include <X11/extensions/Xrandr.h>
 #include <X11/Xlib.h>
 
 // It clashes with out RootWindow.
@@ skipping 123 matching lines @@
       randr_version_minor >= 3;
 
   if (has_xrandr_) {
     int error_base_ignored = 0;
     XRRQueryExtension(xdisplay_, &xrandr_event_base_, &error_base_ignored);
 
     if (ui::PlatformEventSource::GetInstance())
       ui::PlatformEventSource::GetInstance()->AddPlatformEventDispatcher(this);
     XRRSelectInput(xdisplay_,
                    x_root_window_,
-                   RRScreenChangeNotifyMask | RROutputChangeNotifyMask);
+                   RRScreenChangeNotifyMask |
+                   RROutputChangeNotifyMask |
+                   RRCrtcChangeNotifyMask);
 
     displays_ = BuildDisplaysFromXRandRInfo();
   } else {
     displays_ = GetFallbackDisplayList();
   }
 }
 
 DesktopScreenX11::~DesktopScreenX11() {
   if (has_xrandr_ && ui::PlatformEventSource::GetInstance())
     ui::PlatformEventSource::GetInstance()->RemovePlatformEventDispatcher(this);
@@ skipping 155 matching lines @@
 
 bool DesktopScreenX11::CanDispatchEvent(const ui::PlatformEvent& event) {
   return event->type - xrandr_event_base_ == RRScreenChangeNotify ||
          event->type - xrandr_event_base_ == RRNotify;
 }
 
 uint32_t DesktopScreenX11::DispatchEvent(const ui::PlatformEvent& event) {
   if (event->type - xrandr_event_base_ == RRScreenChangeNotify) {
     // Pass the event through to xlib.
     XRRUpdateConfiguration(event);
   } else if (event->type - xrandr_event_base_ == RRNotify) {

[Elliot Glaysher, 2014/04/17 17:40:53]

I was going to ask if there was something you had to do here, but it looks like
RRNotify_CrtcChange is an event subtype of RRNotify.

     // There's some sort of observer dispatch going on here, but I don't think
     // it's the screen's?
     if (configure_timer_.get() && configure_timer_->IsRunning()) {
       configure_timer_->Reset();
     } else {
       configure_timer_.reset(new base::OneShotTimer<DesktopScreenX11>());
       configure_timer_->Start(
           FROM_HERE,
           base::TimeDelta::FromMilliseconds(kConfigureDelayMs),
           this,
@@ skipping 102 matching lines @@
   ProcessDisplayChange(new_displays);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 
 gfx::Screen* CreateDesktopScreen() {
   return new DesktopScreenX11;
 }
 
 }  // namespace views