Revert 232657 "GN: toolchain threading cleanup"

trunk/src/tools/gn/test_with_scope.h

 // Copyright (c) 2013 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 TOOLS_GN_TEST_WITH_SCOPE_H_
 #define TOOLS_GN_TEST_WITH_SCOPE_H_
 
 #include "base/basictypes.h"
 #include "tools/gn/build_settings.h"
 #include "tools/gn/scope.h"
 #include "tools/gn/settings.h"
 #include "tools/gn/toolchain.h"
 
 // A helper class for setting up a Scope that a test can use. It makes a
 // toolchain and sets up all the build state.
 class TestWithScope {
  public:
   TestWithScope();
   ~TestWithScope();
 
   BuildSettings* build_settings() { return &build_settings_; }
   Settings* settings() { return &settings_; }
-  Toolchain* toolchain() { return &toolchain_; }
   Scope* scope() { return &scope_; }
 
  private:
   BuildSettings build_settings_;
+  Toolchain toolchain_;
   Settings settings_;
-  Toolchain toolchain_;
   Scope scope_;
 
   DISALLOW_COPY_AND_ASSIGN(TestWithScope);
 };
 
 #endif  // TOOLS_GN_TEST_WITH_SCOPE_H_