Reduce usage of MessageLoopProxy in base/

base/test/thread_test_helper.cc

Index: base/test/thread_test_helper.cc
diff --git a/base/test/thread_test_helper.cc b/base/test/thread_test_helper.cc
index a91517df3d0ab1996f6727aff56c33b9ac0cdde2..5b5dd9ec91a85e728f5dc4ce66e1a59638b8b100 100644
--- a/base/test/thread_test_helper.cc
+++ b/base/test/thread_test_helper.cc
@@ -6,18 +6,20 @@
 
 #include "base/bind.h"
 #include "base/location.h"
+#include "base/sequenced_task_runner.h"
 #include "base/threading/thread_restrictions.h"
 
 namespace base {
 
-ThreadTestHelper::ThreadTestHelper(MessageLoopProxy* target_thread)
+ThreadTestHelper::ThreadTestHelper(
+    const scoped_refptr<base::SequencedTaskRunner>& target_task_runner)
     : test_result_(false),
-      target_thread_(target_thread),
+      target_task_runner_(target_task_runner),
       done_event_(false, false) {
 }
 
 bool ThreadTestHelper::Run() {
-  if (!target_thread_->PostTask(
+  if (!target_task_runner_->PostTask(
           FROM_HERE, base::Bind(&ThreadTestHelper::RunInThread, this))) {
     return false;
   }