GN threading refactor

tools/gn/config.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_CONFIG_H_
 #define TOOLS_GN_CONFIG_H_
 
 #include "base/compiler_specific.h"
 #include "tools/gn/config_values.h"
 #include "tools/gn/item.h"
 
-class Err;
-class ItemTree;
-class LocationRange;
-class Settings;
-
 // Represents a named config in the dependency graph.
 class Config : public Item {
  public:
   Config(const Settings* settings, const Label& label);
   virtual ~Config();
 
   virtual Config* AsConfig() OVERRIDE;
   virtual const Config* AsConfig() const OVERRIDE;
 
   ConfigValues& config_values() { return config_values_; }
   const ConfigValues& config_values() const { return config_values_; }
 
-  // Gets or creates a config.
-  //
-  // This is like the TargetManager is for Targets, but Configs are so much
-  // simpler that this one function is all we need.
-  static Config* GetConfig(const Settings* settings,
-                           const LocationRange& specified_from_here,
-                           const Label& label,
-                           Item* dep_from,
-                           Err* err);
-
  private:
   ConfigValues config_values_;
 
   DISALLOW_COPY_AND_ASSIGN(Config);
 };
 
 #endif  // TOOLS_GN_CONFIG_H_