GN: Use std::unique_ptr in Loader::ToolchainRecordMap.

tools/gn/loader.h

Index: tools/gn/loader.h
diff --git a/tools/gn/loader.h b/tools/gn/loader.h
index 3d61fe4b4e867e005c686305d573100220304880..37f708563c49b73e4f3591c2aee8d46df89e6630 100644
--- a/tools/gn/loader.h
+++ b/tools/gn/loader.h
@@ -6,6 +6,7 @@
 #define TOOLS_GN_LOADER_H_
 
 #include <map>
+#include <memory>
 #include <set>
 
 #include "base/callback.h"
@@ -173,8 +174,7 @@ class LoaderImpl : public Loader {
   Label default_toolchain_label_;
 
   // Records for the build config file loads.
-  // Owning pointers.
-  typedef std::map<Label, ToolchainRecord*> ToolchainRecordMap;
+  typedef std::map<Label, std::unique_ptr<ToolchainRecord>> ToolchainRecordMap;
   ToolchainRecordMap toolchain_records_;
 };