Support more configurability in GN toolchains

tools/gn/config_values_extractors_unittest.cc

 // 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.
 
 #include <sstream>
 
 #include "testing/gtest/include/gtest/gtest.h"
 #include "tools/gn/config.h"
 #include "tools/gn/config_values_extractors.h"
 #include "tools/gn/target.h"
@@ skipping 27 matching lines @@
   dep2_all.config_values().cflags().push_back("--dep2-all");
   dep2_all.config_values().include_dirs().push_back(SourceDir("//dep2/all/"));
 
   Config dep2_direct(setup.settings(), Label(SourceDir("//dep2/"), "direct"));
   dep2_direct.config_values().cflags().push_back("--dep2-direct");
   dep2_direct.config_values().include_dirs().push_back(
       SourceDir("//dep2/direct/"));
 
   Target dep2(setup.settings(), Label(SourceDir("//dep2/"), "dep2"));
   dep2.set_output_type(Target::SOURCE_SET);
+  dep2.SetToolchain(setup.toolchain());
   dep2.all_dependent_configs().push_back(LabelConfigPair(&dep2_all));
   dep2.direct_dependent_configs().push_back(LabelConfigPair(&dep2_direct));
 
   // Set up dep1, direct and all dependent configs.
   Config dep1_all(setup.settings(), Label(SourceDir("//dep1/"), "all"));
   dep1_all.config_values().cflags().push_back("--dep1-all");
   dep1_all.config_values().include_dirs().push_back(SourceDir("//dep1/all/"));
 
   Config dep1_direct(setup.settings(), Label(SourceDir("//dep1/"), "direct"));
   dep1_direct.config_values().cflags().push_back("--dep1-direct");
   dep1_direct.config_values().include_dirs().push_back(
       SourceDir("//dep1/direct/"));
 
   Target dep1(setup.settings(), Label(SourceDir("//dep1/"), "dep1"));
   dep1.set_output_type(Target::SOURCE_SET);
+  dep1.SetToolchain(setup.toolchain());
   dep1.all_dependent_configs().push_back(LabelConfigPair(&dep1_all));
   dep1.direct_dependent_configs().push_back(LabelConfigPair(&dep1_direct));
   dep1.deps().push_back(LabelTargetPair(&dep2));
 
   // Set up target, direct and all dependent configs.
   Config target_all(setup.settings(), Label(SourceDir("//target/"), "all"));
   target_all.config_values().cflags().push_back("--target-all");
   target_all.config_values().include_dirs().push_back(
       SourceDir("//target/all/"));
 
   Config target_direct(setup.settings(),
                        Label(SourceDir("//target/"), "direct"));
   target_direct.config_values().cflags().push_back("--target-direct");
   target_direct.config_values().include_dirs().push_back(
       SourceDir("//target/direct/"));
 
   // This config is applied directly to target.
   Config target_config(setup.settings(),
                        Label(SourceDir("//target/"), "config"));
   target_config.config_values().cflags().push_back("--target-config");
   target_config.config_values().include_dirs().push_back(
       SourceDir("//target/config/"));
 
   Target target(setup.settings(), Label(SourceDir("//target/"), "target"));
   target.set_output_type(Target::SOURCE_SET);
+  target.SetToolchain(setup.toolchain());
   target.all_dependent_configs().push_back(LabelConfigPair(&target_all));
   target.direct_dependent_configs().push_back(LabelConfigPair(&target_direct));
   target.configs().push_back(LabelConfigPair(&target_config));
   target.deps().push_back(LabelTargetPair(&dep1));
 
 
   // Additionally add some values directly on "target".
   target.config_values().cflags().push_back("--target");
   target.config_values().include_dirs().push_back(
       SourceDir("//target/"));
@@ skipping 14 matching lines @@
 
   // Verify include dirs by serializing.
   std::ostringstream include_out;
   IncludeWriter include_writer;
   RecursiveTargetConfigToStream<SourceDir, IncludeWriter>(
       &target, &ConfigValues::include_dirs, include_writer, include_out);
   EXPECT_EQ(include_out.str(),
             "//target/ //target/config/ //target/all/ //target/direct/ "
             "//dep1/all/ //dep2/all/ //dep1/direct/ ");
 }