tools/gn: Change auto to not deduce raw pointers.

tools/gn/loader.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "tools/gn/loader.h"
 
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
 #include "base/message_loop/message_loop.h"
 #include "base/single_thread_task_runner.h"
@@ skipping 255 matching lines @@
     our_scope.CheckForUnusedVars(&err);
 
   if (err.has_error()) {
     if (!origin.is_null())
       err.AppendSubErr(Err(origin, "which caused the file to be included."));
     g_scheduler->FailWithError(err);
   }
 
 
   // Pass all of the items that were defined off to the builder.
-  for (auto& item : collected_items) {
+  for (auto*& item : collected_items) {
     settings->build_settings()->ItemDefined(base::WrapUnique(item));
     item = nullptr;
   }
 
   trace.Done();
 
   main_loop_->task_runner()->PostTask(
       FROM_HERE, base::Bind(&LoaderImpl::DidLoadFile, this));
 }
 
@@ skipping 134 matching lines @@
     const SourceFile& file_name,
     const base::Callback<void(const ParseNode*)>& callback,
     Err* err) {
   if (async_load_file_.is_null()) {
     return g_scheduler->input_file_manager()->AsyncLoadFile(
         origin, build_settings, file_name, callback, err);
   }
   return async_load_file_.Run(
       origin, build_settings, file_name, callback, err);
 }