GN: toolchain threading cleanup

tools/gn/toolchain.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_TOOLCHAIN_H_
 #define TOOLS_GN_TOOLCHAIN_H_
 
 #include "base/compiler_specific.h"
 #include "base/strings/string_piece.h"
 #include "tools/gn/item.h"
@@ skipping 52 matching lines @@
     std::string deps;
     std::string description;
     std::string lib_dir_prefix;
     std::string lib_prefix;
     std::string pool;
     std::string restat;
     std::string rspfile;
     std::string rspfile_content;
   };
 
-  Toolchain(const Label& label);
+  Toolchain(const Settings* settings, const Label& label);
   virtual ~Toolchain();
 
   // Item overrides.
   virtual Toolchain* AsToolchain() OVERRIDE;
   virtual const Toolchain* AsToolchain() const OVERRIDE;
 
   // Returns TYPE_NONE on failure.
   static ToolType ToolNameToType(const base::StringPiece& str);
   static std::string ToolTypeToName(ToolType type);
 
   const Tool& GetTool(ToolType type) const;
   void SetTool(ToolType type, const Tool& t);
 
   const std::string& environment() const { return environment_; }
   void set_environment(const std::string& env) { environment_ = env; }
 
-  bool is_default() const { return is_default_; }
-  void set_is_default(bool id) { is_default_ = id; }
-
   // Specifies build argument overrides that will be set on the base scope. It
   // will be as if these arguments were passed in on the command line. This
   // allows a toolchain to override the OS type of the default toolchain or
   // pass in other settings.
   Scope::KeyValueMap& args() { return args_; }
   const Scope::KeyValueMap& args() const { return args_; }
 
  private:
   Tool tools_[TYPE_NUMTYPES];
 
-  bool is_default_;
   Scope::KeyValueMap args_;
 
   std::string environment_;
 };
 
 #endif  // TOOLS_GN_TOOLCHAIN_H_