compositor worker: Use a WebThread for the compositor thread.

components/scheduler/child/webthread_impl_for_worker_scheduler.h

Index: components/scheduler/child/webthread_impl_for_worker_scheduler.h
diff --git a/components/scheduler/child/webthread_impl_for_worker_scheduler.h b/components/scheduler/child/webthread_impl_for_worker_scheduler.h
index 37bdff6b870251f529578edd592a81c8b44332d4..306cbd8c8b03e59679f6b71149ec05a80db6b8d5 100644
--- a/components/scheduler/child/webthread_impl_for_worker_scheduler.h
+++ b/components/scheduler/child/webthread_impl_for_worker_scheduler.h
@@ -47,12 +47,11 @@ class SCHEDULER_EXPORT WebThreadImplForWorkerScheduler
   // base::MessageLoop::DestructionObserver implementation.
   void WillDestroyCurrentMessageLoop() override;
 
+ protected:
+  base::Thread* thread() const { return thread_.get(); }
+
  private:
-  // Returns whether the base::Thread's task-runner should be used as the
-  // default task runner (returns true), or the default task runner from the
-  // scheduler should be used instead (returns false). The default behaviour is
-  // to use the scheduler's default task runner.
-  virtual bool UseThreadTaskRunnerAsDefault() const;
+  virtual scoped_ptr<scheduler::WorkerScheduler> CreateWorkerScheduler();

[Sami, 2016/01/14 13:55:04]

Looks like this patch is relative to your older one instead of tip-of-tree.
Could you rebase?

[sadrul, 2016/01/14 15:20:40]

Yep, sorry. Done.

 
   void AddTaskObserverInternal(
       base::MessageLoop::TaskObserver* observer) override;