Revert 232657 "GN: toolchain threading cleanup"

trunk/src/tools/gn/settings.h

Index: trunk/src/tools/gn/settings.h
===================================================================
--- trunk/src/tools/gn/settings.h	(revision 232660)
+++ trunk/src/tools/gn/settings.h	(working copy)
@@ -38,18 +38,19 @@
   // toolchain's outputs. It should have no slashes in it. The default
   // toolchain should use an empty string.
   Settings(const BuildSettings* build_settings,
+           const Toolchain* toolchain,
            const std::string& output_subdir_name);
   ~Settings();
 
   const BuildSettings* build_settings() const { return build_settings_; }
 
-  const Label& toolchain_label() const { return toolchain_label_; }
-  void set_toolchain_label(const Label& l) { toolchain_label_ = l; }
+  // Danger: this must only be used for getting the toolchain label until the
+  // toolchain has been resolved. Otherwise, it will be modified on an
+  // arbitrary thread when the toolchain invocation is found. Generally, you
+  // will only read this from the target generation where we know everything
+  // has been resolved and won't change.
+  const Toolchain* toolchain() const { return toolchain_; }
 
-  // Indicates if this corresponds to the default toolchain.
-  bool is_default() const { return is_default_; }
-  void set_is_default(bool id) { is_default_ = id; }
-
   bool IsMac() const { return target_os_ == MAC; }
   bool IsLinux() const { return target_os_ == LINUX; }
   bool IsWin() const { return target_os_ == WIN; }
@@ -93,8 +94,7 @@
  private:
   const BuildSettings* build_settings_;
 
-  Label toolchain_label_;
-  bool is_default_;
+  const Toolchain* toolchain_;
 
   TargetOS target_os_;