Check for NULL NativeView in linux/mac Screen::GetDisplayNearestWindow().

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 139 matching lines @@
 int DesktopScreenX11::GetNumDisplays() const {
   return displays_.size();
 }
 
 std::vector<gfx::Display> DesktopScreenX11::GetAllDisplays() const {
   return displays_;
 }
 
 gfx::Display DesktopScreenX11::GetDisplayNearestWindow(
     gfx::NativeView window) const {
+  if (!window)
+    return GetPrimaryDisplay();
+
   // Getting screen bounds here safely is hard.
   //
   // You'd think we'd be able to just call window->GetBoundsInScreen(), but we
   // can't because |window| (and the associated WindowEventDispatcher*) can be
   // partially initialized at this point; WindowEventDispatcher initializations
   // call through into GetDisplayNearestWindow(). But the X11 resources are
   // created before we create the aura::WindowEventDispatcher. So we ask what
   // the DRWHX11 believes the window bounds are instead of going through the
   // aura::Window's screen bounds.
   aura::WindowTreeHost* host = window->GetHost();
@@ skipping 189 matching lines @@
   change_notifier_.NotifyDisplaysChanged(old_displays, displays_);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 
 gfx::Screen* CreateDesktopScreen() {
   return new DesktopScreenX11;
 }
 
 }  // namespace views