Add testonly flag to GN

tools/gn/ninja_target_writer_unittest.cc

Index: tools/gn/ninja_target_writer_unittest.cc
diff --git a/tools/gn/ninja_target_writer_unittest.cc b/tools/gn/ninja_target_writer_unittest.cc
index 67b55e185649d0e88cef86c082fae0f73c205642..08cde8fccdffbb7230aab30efc37f7d88838bbfe 100644
--- a/tools/gn/ninja_target_writer_unittest.cc
+++ b/tools/gn/ninja_target_writer_unittest.cc
@@ -32,6 +32,7 @@ class TestingNinjaTargetWriter : public NinjaTargetWriter {
 
 TEST(NinjaTargetWriter, WriteInputDepsStampAndGetDep) {
   TestWithScope setup;
+  Err err;
 
   // Make a base target that's a hard dep (action).
   Target base_target(setup.settings(), Label(SourceDir("//foo/"), "base"));
@@ -57,9 +58,9 @@ TEST(NinjaTargetWriter, WriteInputDepsStampAndGetDep) {
   action.sources().push_back(SourceFile("//foo/action_source.txt"));
   action.deps().push_back(LabelTargetPair(&target));
 
-  base_target.OnResolved();
-  target.OnResolved();
-  action.OnResolved();
+  ASSERT_TRUE(base_target.OnResolved(&err));
+  ASSERT_TRUE(target.OnResolved(&err));
+  ASSERT_TRUE(action.OnResolved(&err));
 
   // Input deps for the base (should be only the script itself).
   {
@@ -105,6 +106,7 @@ TEST(NinjaTargetWriter, WriteInputDepsStampAndGetDep) {
 // Tests WriteInputDepsStampAndGetDep when toolchain deps are present.
 TEST(NinjaTargetWriter, WriteInputDepsStampAndGetDepWithToolchainDeps) {
   TestWithScope setup;
+  Err err;
 
   // Toolchain dependency. Here we make a target in the same toolchain for
   // simplicity, but in real life (using the Builder) this would be rejected
@@ -114,14 +116,14 @@ TEST(NinjaTargetWriter, WriteInputDepsStampAndGetDepWithToolchainDeps) {
                               Label(SourceDir("//foo/"), "setup"));
   toolchain_dep_target.set_output_type(Target::ACTION);
   toolchain_dep_target.SetToolchain(setup.toolchain());
-  toolchain_dep_target.OnResolved();
+  ASSERT_TRUE(toolchain_dep_target.OnResolved(&err));
   setup.toolchain()->deps().push_back(LabelTargetPair(&toolchain_dep_target));
 
   // Make a binary target
   Target target(setup.settings(), Label(SourceDir("//foo/"), "target"));
   target.set_output_type(Target::EXECUTABLE);
   target.SetToolchain(setup.toolchain());
-  target.OnResolved();
+  ASSERT_TRUE(target.OnResolved(&err));
 
   std::ostringstream stream;
   TestingNinjaTargetWriter writer(&target, setup.toolchain(), stream);