Redirect the MessageLoop's task runner to the renderer scheduler

components/scheduler/test/lazy_scheduler_message_loop_delegate_for_tests.h

 // Copyright 2015 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 COMPONENTS_SCHEDULER_TEST_LAZY_SCHEDULER_MESSAGE_LOOP_DELEGATE_FOR_TESTS_H_
 #define COMPONENTS_SCHEDULER_TEST_LAZY_SCHEDULER_MESSAGE_LOOP_DELEGATE_FOR_TESTS_H_
 
 #include "base/message_loop/message_loop.h"
 #include "components/scheduler/child/nestable_single_thread_task_runner.h"
 
 namespace scheduler {
 
 // This class connects the scheduler to a MessageLoop, but unlike
 // SchedulerMessageLoopDelegate it allows the message loop to be created lazily
 // after the scheduler has been brought up. This is needed in testing scenarios
 // where Blink is initialized before a MessageLoop has been created.
 //
 // TODO(skyostil): Fix the relevant test suites and remove this class
 // (crbug.com/495659).
 class LazySchedulerMessageLoopDelegateForTests
     : public NestableSingleThreadTaskRunner {
  public:
   static scoped_refptr<LazySchedulerMessageLoopDelegateForTests> Create();
 
   // NestableSingleThreadTaskRunner implementation
+  void SetDefaultTaskRunner(
+      scoped_refptr<base::SingleThreadTaskRunner> task_runner) override;
   bool PostDelayedTask(const tracked_objects::Location& from_here,
                        const base::Closure& task,
                        base::TimeDelta delay) override;
   bool PostNonNestableDelayedTask(const tracked_objects::Location& from_here,
                                   const base::Closure& task,
                                   base::TimeDelta delay) override;
   bool RunsTasksOnCurrentThread() const override;
   bool IsNested() const override;
   void AddTaskObserver(base::MessageLoop::TaskObserver* task_observer) override;
   void RemoveTaskObserver(
       base::MessageLoop::TaskObserver* task_observer) override;
 
  private:
   LazySchedulerMessageLoopDelegateForTests();
   ~LazySchedulerMessageLoopDelegateForTests() override;
 
   bool HasMessageLoop() const;
   base::MessageLoop* EnsureMessageLoop() const;
 
   mutable base::MessageLoop* message_loop_;
   base::PlatformThreadId thread_id_;
 
   // Task observers which have not yet been registered to a message loop. Not
   // owned.
   mutable base::hash_set<base::MessageLoop::TaskObserver*> pending_observers_;
 
+  // A task runner which hasn't yet been overridden in the message loop.
+  mutable scoped_refptr<base::SingleThreadTaskRunner> pending_task_runner_;
+
   DISALLOW_COPY_AND_ASSIGN(LazySchedulerMessageLoopDelegateForTests);
 };
 
 }  // namespace scheduler
 
 #endif  // COMPONENTS_SCHEDULER_TEST_LAZY_SCHEDULER_MESSAGE_LOOP_DELEGATE_FOR_TESTS_H_