Revert 124461 - Remove the singleton instance get/delete methods from RootWindow (yay)

ash/test/ash_test_base.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 "ash/test/ash_test_base.h"
 
 #include "ash/shell.h"
 #include "ash/test/test_shell_delegate.h"
 #include "ui/aura/root_window.h"
 #include "ui/gfx/compositor/layer_animator.h"
 
 namespace ash {
 namespace test {
 
 AshTestBase::AshTestBase() {
+  helper_.InitRootWindow(Shell::GetRootWindow());
 }
 
 AshTestBase::~AshTestBase() {
+  // Ensure that we don't use the previously-allocated static RootWindow object
+  // later -- on Linux, it holds a reference to our message loop's X connection.
+  aura::RootWindow::DeleteInstance();
 }
 
 void AshTestBase::SetUp() {
+  helper_.SetUp();
+
   // Creates Shell and hook with Desktop.
   TestShellDelegate* delegate = new TestShellDelegate;
   Shell::WindowMode window_mode = Shell::MODE_OVERLAPPING;
   if (GetOverrideWindowMode(&window_mode))
     delegate->SetOverrideWindowMode(window_mode);
   ash::Shell::CreateInstance(delegate);
 
-  helper_.SetUp();
-  helper_.InitRootWindow(Shell::GetRootWindow());
-
   // Disable animations during tests.
   ui::LayerAnimator::set_disable_animations_for_test(true);
 }
 
 void AshTestBase::TearDown() {
   // Flush the message loop to finish pending release tasks.
   RunAllPendingInMessageLoop();
 
-  helper_.TearDown();
-
   // Tear down the shell.
   Shell::DeleteInstance();
+
+  helper_.TearDown();
 }
 
 bool AshTestBase::GetOverrideWindowMode(Shell::WindowMode* window_mode) {
   return false;
 }
 
 void AshTestBase::RunAllPendingInMessageLoop() {
   helper_.RunAllPendingInMessageLoop(Shell::GetRootWindow());
 }
 
 }  // namespace test
 }  // namespace ash