Allow GN configs to have sub-configs.

tools/gn/target.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/target.h"
 
 #include "base/bind.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "tools/gn/config_values_extractors.h"
@@ skipping 435 matching lines @@
   // Track where the current settings came from for issuing errors.
   const Label* pch_header_settings_from = NULL;
   if (config_values_.has_precompiled_headers())
     pch_header_settings_from = &label();
 
   for (ConfigValuesIterator iter(this); !iter.done(); iter.Next()) {
     if (!iter.GetCurrentConfig())
       continue;  // Skip the one on the target itself.
 
     const Config* config = iter.GetCurrentConfig();
-    const ConfigValues& cur = config->config_values();
+    const ConfigValues& cur = config->resolved_values();
     if (!cur.has_precompiled_headers())
       continue;  // This one has no precompiled header info, skip.
 
     if (config_values_.has_precompiled_headers()) {
       // Already have a precompiled header values, the settings must match.
       if (config_values_.precompiled_header() != cur.precompiled_header() ||
           config_values_.precompiled_source() != cur.precompiled_source()) {
         *err = Err(defined_from(),
             "Precompiled header setting conflict.",
             "The target " + label().GetUserVisibleName(false) + "\n"
@@ skipping 87 matching lines @@
     return;  // Not in output dir, this is OK.
 
   // Tell the scheduler about unknown files. This will be noted for later so
   // the list of files written by the GN build itself (often response files)
   // can be filtered out of this list.
   OutputFile out_file(settings()->build_settings(), source);
   std::set<const Target*> seen_targets;
   if (!EnsureFileIsGeneratedByDependency(this, out_file, true, &seen_targets))
     g_scheduler->AddUnknownGeneratedInput(this, source);
 }