aura: Fix crash in RootWindowHostX11::GetXImage().

ui/aura/root_window_host_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/aura/root_window_host_x11.h"
 
 #include <strings.h>
 #include <X11/cursorfont.h>
 #include <X11/extensions/Xfixes.h>
 #include <X11/extensions/XInput2.h>
@@ skipping 1074 matching lines @@
   delegate_->OnHostMouseEvent(event);
 }
 
 scoped_ptr<ui::XScopedImage> RootWindowHostX11::GetXImage(
     const gfx::Rect& snapshot_bounds) {
   scoped_ptr<ui::XScopedImage> image(new ui::XScopedImage(
       XGetImage(xdisplay_, xwindow_,
                 snapshot_bounds.x(), snapshot_bounds.y(),
                 snapshot_bounds.width(), snapshot_bounds.height(),
                 AllPlanes, ZPixmap)));
-  if (!image) {
+  if (!image->get()) {

[tfarina, 2013/08/10 17:08:58]

ok.

     LOG(ERROR) << "XGetImage failed";
     image.reset();
   }
   return image.Pass();
 }
 
 void RootWindowHostX11::UpdateIsInternalDisplay() {
   RootWindow* root_window = GetRootWindow();
   gfx::Screen* screen = gfx::Screen::GetScreenFor(root_window);
   gfx::Display display = screen->GetDisplayNearestWindow(root_window);
@@ skipping 40 matching lines @@
 }
 
 namespace test {
 
 void SetUseOverrideRedirectWindowByDefault(bool override_redirect) {
   default_override_redirect = override_redirect;
 }
 
 }  // namespace test
 }  // namespace aura