Revert 232657 "GN: toolchain threading cleanup"

trunk/src/tools/gn/ninja_target_writer.h

Index: trunk/src/tools/gn/ninja_target_writer.h
===================================================================
--- trunk/src/tools/gn/ninja_target_writer.h	(revision 232660)
+++ trunk/src/tools/gn/ninja_target_writer.h	(working copy)
@@ -19,9 +19,7 @@
 // generated by the NinjaBuildWriter.
 class NinjaTargetWriter {
  public:
-  NinjaTargetWriter(const Target* target,
-                    const Toolchain* toolchain,
-                    std::ostream& out);
+  NinjaTargetWriter(const Target* target, std::ostream& out);
   virtual ~NinjaTargetWriter();
 
   static void RunAndWriteFile(const Target* target);
@@ -29,6 +27,9 @@
   virtual void Run() = 0;
 
  protected:
+  // Returns the toolchain associated with the target.
+  const Toolchain* GetToolchain() const;
+
   // Returns the string to be appended to source rules that encodes the
   // order-only dependencies for the current target. This will include the
   // "|" character so can just be appended to the source rules. If there are no
@@ -40,7 +41,6 @@
 
   const Settings* settings_;  // Non-owning.
   const Target* target_;  // Non-owning.
-  const Toolchain* toolchain_;  // Non-owning.
   std::ostream& out_;
   PathOutput path_output_;