Allow paths to be resolved in the GN args file

tools/gn/setup.cc

 // 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.
 
 #include "tools/gn/setup.h"
 
 #include <stdlib.h>
 
 #include <algorithm>
 #include <sstream>
@@ skipping 142 matching lines @@
 const char Setup::kBuildArgFileName[] = "args.gn";
 
 Setup::Setup()
     : build_settings_(),
       loader_(new LoaderImpl(&build_settings_)),
       builder_(new Builder(loader_.get())),
       root_build_file_("//BUILD.gn"),
       check_for_bad_items_(true),
       check_for_unused_overrides_(true),
       check_public_headers_(false),
-      empty_settings_(&empty_build_settings_, std::string()),
-      dotfile_scope_(&empty_settings_),
+      dotfile_settings_(&build_settings_, std::string()),
+      dotfile_scope_(&dotfile_settings_),
       fill_arguments_(true) {
-  empty_settings_.set_toolchain_label(Label());
+  dotfile_settings_.set_toolchain_label(Label());
   build_settings_.set_item_defined_callback(
       base::Bind(&ItemDefinedCallback, scheduler_.main_loop(), builder_));
 
   loader_->set_complete_callback(base::Bind(&DecrementWorkCount));
   // The scheduler's main loop wasn't created when the Loader was created, so
   // we need to set it now.
   loader_->set_main_loop(scheduler_.main_loop());
 }
 
 Setup::~Setup() {
@@ skipping 156 matching lines @@
     err.PrintToStdout();
     return false;
   }
 
   args_root_ = Parser::Parse(args_tokens_, &err);
   if (err.has_error()) {
     err.PrintToStdout();
     return false;
   }
 
-  Scope arg_scope(&empty_settings_);
+  Scope arg_scope(&dotfile_settings_);
   args_root_->Execute(&arg_scope, &err);
   if (err.has_error()) {
     err.PrintToStdout();
     return false;
   }
 
   // Save the result of the command args.
   Scope::KeyValueMap overrides;
   arg_scope.GetCurrentScopeValues(&overrides);
   build_settings_.build_args().AddArgOverrides(overrides);
@@ skipping 268 matching lines @@
         err.PrintToStdout();
         return false;
       }
       whitelist->insert(current_dir.ResolveRelativeFile(item.string_value()));
     }
     build_settings_.set_exec_script_whitelist(whitelist.Pass());
   }
 
   return true;
 }