[MessageLoop]: Replace MessageLoopCurrent::task_runner() in...

[MessageLoop]: Replace MessageLoopCurrent::task_runner() in /content/public/test/test_download_http_response.cc.

MessageLoopCurrent::task_runner() is depecated.
This CL replaces it with with ThreadTaskRunnerHandle::Get().
A small step towards deleting MessageLoop.

This CL was generated with git cl split.
Refer to the top-level CL if necessary :
https://chromium-review.googlesource.com/c/chromium/src/+/1631693

Please CQ if LGTY!

This CL was uploaded by git cl split.

R=dtrainor@chromium.org

Bug: 616447
Change-Id: Ib6d3b417344ca2ece7c09d98b52a8f6e79b480f4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1636358
Auto-Submit: Etienne Pierre-Doray <etiennep@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Commit-Queue: David Trainor <dtrainor@chromium.org>
Cr-Commit-Position: refs/heads/master@{#664793}

content/public/test/test_download_http_response.cc

@@ -10,7 +10,6 @@
 #include "base/bind_helpers.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
-#include "base/message_loop/message_loop_current.h"
 #include "base/numerics/ranges.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string_util.h"
@@ -618,7 +617,7 @@ std::unique_ptr<net::test_server::HttpResponse>
 TestDownloadResponseHandler::HandleTestDownloadRequest(
     const TestDownloadHttpResponse::OnResponseSentCallback& callback,
     const net::test_server::HttpRequest& request) {
-  server_task_runner_ = base::MessageLoopCurrent::Get()->task_runner();
+  server_task_runner_ = base::ThreadTaskRunnerHandle::Get();
 
   if (request.headers.find(net::HttpRequestHeaders::kHost) ==
       request.headers.end()) {