Reduce usage of MessageLoopProxy in base/

base/test/thread_test_helper.h

Index: base/test/thread_test_helper.h
diff --git a/base/test/thread_test_helper.h b/base/test/thread_test_helper.h
index f6817b520ed3bc57844ca17015887d6f382aa273..79c59ffe1b59c30d19bcf8963a86268716343564 100644
--- a/base/test/thread_test_helper.h
+++ b/base/test/thread_test_helper.h
@@ -7,11 +7,12 @@
 
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
-#include "base/message_loop/message_loop_proxy.h"
 #include "base/synchronization/waitable_event.h"
 
 namespace base {
 
+class SequencedTaskRunner;
+
 // Helper class that executes code on a given thread while blocking on the
 // invoking thread. To use, derive from this class and overwrite RunTest. An
 // alternative use of this class is to use it directly.  It will then block
@@ -19,7 +20,7 @@ namespace base {
 class ThreadTestHelper : public RefCountedThreadSafe<ThreadTestHelper> {
  public:
   explicit ThreadTestHelper(
-      const scoped_refptr<MessageLoopProxy>& target_thread);
+      const scoped_refptr<SequencedTaskRunner>& target_task_runner);
 
   // True if RunTest() was successfully executed on the target thread.
   bool Run() WARN_UNUSED_RESULT;
@@ -38,7 +39,7 @@ class ThreadTestHelper : public RefCountedThreadSafe<ThreadTestHelper> {
   void RunInThread();
 
   bool test_result_;
-  scoped_refptr<MessageLoopProxy> target_thread_;
+  scoped_refptr<SequencedTaskRunner> target_task_runner_;
   WaitableEvent done_event_;
 
   DISALLOW_COPY_AND_ASSIGN(ThreadTestHelper);