Mark Scoped(Async)TaskScheduler as deprecated.

base/test/scoped_task_scheduler.h

 // Copyright 2016 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_SCOPED_TASK_SCHEDULER_H_
 #define BASE_TEST_SCOPED_TASK_SCHEDULER_H_
 
 #include "base/macros.h"
 #include "base/threading/thread_checker.h"
 
 namespace base {
 
 class MessageLoop;
 class TaskScheduler;
 
 namespace test {
 
+// DEPRECATED. Use ScopedTaskEnvironment instead.
+//
+// TODO(fdoray): Replace ScopedTaskScheduler instances by ScopedTaskEnvironment.
+// https://crbug.com/708584
+//
 // Allows usage of the base/task_scheduler/post_task.h API within its scope.
 //
 // To run pending tasks synchronously, call RunLoop::Run/RunUntilIdle() on the
 // thread where the ScopedTaskScheduler lives. The destructor runs remaining
 // BLOCK_SHUTDOWN tasks synchronously.
 //
 // Note: ScopedTaskScheduler intentionally breaks the TaskScheduler contract of
 // always running its tasks on threads it owns, instead opting to run its tasks
 // on the main thread for determinism in tests. Components that depend on
 // TaskScheduler using independent threads should use ScopedAsyncTaskScheduler
@@ skipping 65 matching lines @@
   const TaskScheduler* task_scheduler_ = nullptr;
   ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedTaskScheduler);
 };
 
 }  // namespace test
 }  // namespace base
 
 #endif  // BASE_TEST_SCOPED_TASK_SCHEDULER_H_