GN: toolchain threading cleanup

tools/gn/setup.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_SETUP_H_
 #define TOOLS_GN_SETUP_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 73 matching lines @@
   // Run config file.
   bool RunConfigFile();
 
   bool FillOtherConfig(const CommandLine& cmdline);
 
   Scheduler scheduler_;
 
   // These empty settings and toolchain are used to interpret the command line
   // and dot file.
   BuildSettings empty_build_settings_;
-  Toolchain empty_toolchain_;
   Settings empty_settings_;
   Scope dotfile_scope_;
 
   // State for invoking the dotfile.
   base::FilePath dotfile_name_;
   scoped_ptr<InputFile> dotfile_input_file_;
   std::vector<Token> dotfile_tokens_;
   scoped_ptr<ParseNode> dotfile_root_;
 
   // State for invoking the command line args. We specifically want to keep
@@ skipping 23 matching lines @@
   // These are the two parts of Run() in the regular setup, not including the
   // call to actually run the message loop.
   void RunPreMessageLoop();
   bool RunPostMessageLoop();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(DependentSetup);
 };
 
 #endif  // TOOLS_GN_SETUP_H_