Rename the aura_shell namespace to ash

ash/test/aura_shell_test_base.h

 // 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.
 
 #ifndef ASH_TEST_AURA_SHELL_TEST_BASE_H_
 #define ASH_TEST_AURA_SHELL_TEST_BASE_H_
 #pragma once
 
 #include "base/compiler_specific.h"
 #include "ui/aura/test/aura_test_base.h"
 
-namespace aura_shell {
+namespace ash {
 namespace test {
 
 class AuraShellTestBase : public aura::test::AuraTestBase {
  public:
   AuraShellTestBase();
   virtual ~AuraShellTestBase();
 
   // testing::Test:
   virtual void SetUp() OVERRIDE;
   virtual void TearDown() OVERRIDE;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(AuraShellTestBase);
 };
 
 }  // namespace test
-}  // namespace aura_shell
+}  // namespace ash
 
 #endif  // ASH_TEST_AURA_SHELL_TEST_BASE_H_