GN: toolchain threading cleanup

tools/gn/ninja_target_writer.cc

Index: tools/gn/ninja_target_writer.cc
diff --git a/tools/gn/ninja_target_writer.cc b/tools/gn/ninja_target_writer.cc
index d73c873271d0784a252be41dea5e7b866b6ff663..bdc0472417cc476928c8f22ec3ccb9662f3b6400 100644
--- a/tools/gn/ninja_target_writer.cc
+++ b/tools/gn/ninja_target_writer.cc
@@ -19,9 +19,12 @@
 #include "tools/gn/target.h"
 #include "tools/gn/trace.h"
 
-NinjaTargetWriter::NinjaTargetWriter(const Target* target, std::ostream& out)
+NinjaTargetWriter::NinjaTargetWriter(const Target* target,
+                                     const Toolchain* toolchain,
+                                     std::ostream& out)
     : settings_(target->settings()),
       target_(target),
+      toolchain_(toolchain),
       out_(out),
       path_output_(settings_->build_settings()->build_dir(),
                    ESCAPE_NINJA, true),
@@ -45,7 +48,7 @@ void NinjaTargetWriter::RunAndWriteFile(const Target* target) {
 
   ScopedTrace trace(TraceItem::TRACE_FILE_WRITE,
                     target->label().GetUserVisibleName(false));
-  trace.SetToolchain(settings->toolchain()->label());
+  trace.SetToolchain(settings->toolchain_label());
 
   base::FilePath ninja_file(settings->build_settings()->GetFullPath(
       helper.GetNinjaFileForTarget(target).GetSourceFile(
@@ -54,6 +57,10 @@ void NinjaTargetWriter::RunAndWriteFile(const Target* target) {
   if (g_scheduler->verbose_logging())
     g_scheduler->Log("Writing", FilePathToUTF8(ninja_file));
 
+  const Toolchain* tc = settings->build_settings()->toolchain_manager()
+      .GetToolchainDefinitionUnlocked(settings->toolchain_label());
+  CHECK(tc);
+
   file_util::CreateDirectory(ninja_file.DirName());
 
   // It's rediculously faster to write to a string and then write that to
@@ -62,19 +69,19 @@ void NinjaTargetWriter::RunAndWriteFile(const Target* target) {
 
   // Call out to the correct sub-type of writer.
   if (target->output_type() == Target::COPY_FILES) {
-    NinjaCopyTargetWriter writer(target, file);
+    NinjaCopyTargetWriter writer(target, tc, file);
     writer.Run();
   } else if (target->output_type() == Target::CUSTOM) {
-    NinjaScriptTargetWriter writer(target, file);
+    NinjaScriptTargetWriter writer(target, tc, file);
     writer.Run();
   } else if (target->output_type() == Target::GROUP) {
-    NinjaGroupTargetWriter writer(target, file);
+    NinjaGroupTargetWriter writer(target, tc, file);
     writer.Run();
   } else if (target->output_type() == Target::EXECUTABLE ||
              target->output_type() == Target::STATIC_LIBRARY ||
              target->output_type() == Target::SHARED_LIBRARY ||
              target->output_type() == Target::SOURCE_SET) {
-    NinjaBinaryTargetWriter writer(target, file);
+    NinjaBinaryTargetWriter writer(target, tc, file);
     writer.Run();
   } else {
     CHECK(0);
@@ -85,10 +92,6 @@ void NinjaTargetWriter::RunAndWriteFile(const Target* target) {
                        static_cast<int>(contents.size()));
 }
 
-const Toolchain* NinjaTargetWriter::GetToolchain() const {
-  return target_->settings()->toolchain();
-}
-
 std::string NinjaTargetWriter::GetSourcesImplicitDeps() const {
   std::ostringstream ret;
   ret << " |";