Hook up link pools in GN.

tools/gn/tool.h

 // Copyright 2014 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_TOOL_H_
 #define TOOLS_GN_TOOL_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 102 matching lines @@
   }
 
   const std::string& output_prefix() const {
     return output_prefix_;
   }
   void set_output_prefix(const std::string& s) {
     DCHECK(!complete_);
     output_prefix_ = s;
   }
 
-  const std::string& pool() const {
-    return pool_;
-  }
-  void set_pool(const std::string& s) {
-    DCHECK(!complete_);
-    pool_ = s;
-  }
-
   bool restat() const {
     return restat_;
   }
   void set_restat(bool r) {
     DCHECK(!complete_);
     restat_ = r;
   }
 
   const SubstitutionPattern& rspfile() const {
     return rspfile_;
@@ skipping 34 matching lines @@
   std::string default_output_extension_;
   SubstitutionPattern depfile_;
   DepsFormat depsformat_;
   SubstitutionPattern description_;
   std::string lib_switch_;
   std::string lib_dir_switch_;
   SubstitutionList outputs_;
   SubstitutionPattern link_output_;
   SubstitutionPattern depend_output_;
   std::string output_prefix_;
-  std::string pool_;
   bool restat_;
   SubstitutionPattern rspfile_;
   SubstitutionPattern rspfile_content_;
 
   bool complete_;
 
   SubstitutionBits substitution_bits_;
 
   DISALLOW_COPY_AND_ASSIGN(Tool);
 };
 
 #endif  // TOOLS_GN_TOOL_H_