Add testonly flag to GN

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 10 matching lines @@
 struct IncludeWriter {
   void operator()(const SourceDir& dir, std::ostream& out) const {
     out << dir.value() << " ";
   }
 };
 
 }  // namespace
 
 TEST(ConfigValuesExtractors, IncludeOrdering) {
   TestWithScope setup;
+  Err err;
 
   // Construct a chain of dependencies: target -> dep1 -> dep2
   // Add representative values: cflags (opaque, always copied) and include_dirs
   // (uniquified) to each one so we can check what comes out the other end.
 
   // Set up dep2, direct and all dependent configs.
   Config dep2_all(setup.settings(), Label(SourceDir("//dep2/"), "all"));
   dep2_all.config_values().cflags().push_back("--dep2-all");
   dep2_all.config_values().include_dirs().push_back(SourceDir("//dep2/all/"));
 
@@ skipping 52 matching lines @@
   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/"));
 
   // Mark targets resolved. This should push dependent configs.
-  dep2.OnResolved();
-  dep1.OnResolved();
-  target.OnResolved();
+  ASSERT_TRUE(dep2.OnResolved(&err));
+  ASSERT_TRUE(dep1.OnResolved(&err));
+  ASSERT_TRUE(target.OnResolved(&err));
 
   // Verify cflags by serializing.
   std::ostringstream flag_out;
   FlagWriter flag_writer;
   RecursiveTargetConfigToStream<std::string, FlagWriter>(
       &target, &ConfigValues::cflags, flag_writer, flag_out);
   EXPECT_EQ(flag_out.str(),
             "--target --target-config --target-all --target-direct "
             "--dep1-all --dep2-all --dep1-direct ");
 
   // 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/ ");
 }