Make ThreadTestHelper sequence-friendly.

base/test/thread_test_helper.h

 // Copyright (c) 2011 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.
 
 #ifndef BASE_TEST_THREAD_TEST_HELPER_H_
 #define BASE_TEST_THREAD_TEST_HELPER_H_
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
-#include "base/single_thread_task_runner.h"
+#include "base/sequenced_task_runner.h"
 #include "base/synchronization/waitable_event.h"
 
 namespace base {
 
-// 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
-// until all pending tasks on a given thread have been executed.
+// Helper class that executes code on a given target sequence/thread while
+// blocking on the invoking sequence/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 until all pending tasks on a given sequence/thread have been
+// executed.
 class ThreadTestHelper : public RefCountedThreadSafe<ThreadTestHelper> {
  public:
-  explicit ThreadTestHelper(
-      scoped_refptr<SingleThreadTaskRunner> target_thread);
+  explicit ThreadTestHelper(scoped_refptr<SequencedTaskRunner> target_sequence);
 
-  // True if RunTest() was successfully executed on the target thread.
+  // True if RunTest() was successfully executed on the target sequence.
   bool Run() WARN_UNUSED_RESULT;
 
   virtual void RunTest();
 
  protected:
   friend class RefCountedThreadSafe<ThreadTestHelper>;
 
   virtual ~ThreadTestHelper();
 
   // Use this method to store the result of RunTest().
   void set_test_result(bool test_result) { test_result_ = test_result; }
 
  private:
-  void RunInThread();
+  void RunOnSequence();
 
   bool test_result_;
-  scoped_refptr<SingleThreadTaskRunner> target_thread_;
+  scoped_refptr<SequencedTaskRunner> target_sequence_;
   WaitableEvent done_event_;
 
   DISALLOW_COPY_AND_ASSIGN(ThreadTestHelper);
 };
 
 }  // namespace base
 
 #endif  // BASE_TEST_THREAD_TEST_HELPER_H_