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 72097f2b95b77fca05e7644406c655cb816b12c3..f3344ffdfe826510b1c9c1fb4e0fba8e417eefe3 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();
 
@@ -844,7 +844,7 @@ 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) ||