Convert //tools to use std::unique_ptr

tools/gn/function_toolchain.cc

Index: tools/gn/function_toolchain.cc
diff --git a/tools/gn/function_toolchain.cc b/tools/gn/function_toolchain.cc
index 727be54d7362ddc85e3d4b125ef77aff8f5974c7..d2baf71d46247b49c7e024b347f0ff315c0072f6 100644
--- a/tools/gn/function_toolchain.cc
+++ b/tools/gn/function_toolchain.cc
@@ -324,7 +324,7 @@ Value RunToolchain(Scope* scope,
 
   // This object will actually be copied into the one owned by the toolchain
   // manager, but that has to be done in the lock.
-  scoped_ptr<Toolchain> toolchain(new Toolchain(scope->settings(), label));
+  std::unique_ptr<Toolchain> toolchain(new Toolchain(scope->settings(), label));
   toolchain->set_defined_from(function);
   toolchain->visibility().SetPublic();
 
@@ -840,7 +840,7 @@ Value RunTool(Scope* scope,
     subst_output_validator = &IsValidToolSubstitution;
   }
 
-  scoped_ptr<Tool> tool(new Tool);
+  std::unique_ptr<Tool> tool(new Tool);
 
   if (!ReadPattern(&block_scope, "command", subst_validator, tool.get(),
                    &Tool::set_command, err) ||