Reduce/remove usage of BrowserThread in content/browser/loader.

content/browser/loader/temporary_file_stream.cc

 // Copyright 2014 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 "content/browser/loader/temporary_file_stream.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/files/file_proxy.h"
 #include "base/memory/ref_counted.h"
+#include "content/browser/loader/loader_globals.h"
 #include "content/public/browser/browser_thread.h"
 #include "net/base/file_stream.h"
 #include "storage/browser/blob/shareable_file_reference.h"
 
 using storage::ShareableFileReference;
 
 namespace content {
 
 namespace {
 
 void DidCreateTemporaryFile(const CreateTemporaryFileStreamCallback& callback,
                             std::unique_ptr<base::FileProxy> file_proxy,
                             base::File::Error error_code,
                             const base::FilePath& file_path) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  DCHECK(
+      LoaderGlobals::Get()->io_thread_task_runner()->BelongsToCurrentThread());
 
   if (!file_proxy->IsValid()) {
     callback.Run(error_code, std::unique_ptr<net::FileStream>(), NULL);
     return;
   }
 
   scoped_refptr<base::TaskRunner> task_runner =
       BrowserThread::GetTaskRunnerForThread(BrowserThread::FILE);
 
   // Cancelled or not, create the deletable_file so the temporary is cleaned up.
   scoped_refptr<ShareableFileReference> deletable_file =
       ShareableFileReference::GetOrCreate(
           file_path,
           ShareableFileReference::DELETE_ON_FINAL_RELEASE,
           task_runner.get());
 
   std::unique_ptr<net::FileStream> file_stream(
       new net::FileStream(file_proxy->TakeFile(), task_runner));
 
   callback.Run(error_code, std::move(file_stream), deletable_file.get());
 }
 
 }  // namespace
 
 void CreateTemporaryFileStream(
     const CreateTemporaryFileStreamCallback& callback) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  DCHECK(
+      LoaderGlobals::Get()->io_thread_task_runner()->BelongsToCurrentThread());

[jam, 2017/03/29 15:44:33]

this is only called by redirect_to_file_resource_handler.cc which isn't planned
to move, so it can use BrowserThread

[ananta, 2017/03/29 19:41:04]

Done.

 
   std::unique_ptr<base::FileProxy> file_proxy(new base::FileProxy(
       BrowserThread::GetTaskRunnerForThread(BrowserThread::FILE).get()));
   base::FileProxy* proxy = file_proxy.get();
   proxy->CreateTemporary(
       base::File::FLAG_ASYNC,
       base::Bind(&DidCreateTemporaryFile, callback, Passed(&file_proxy)));
 }
 
 }  // namespace content