[Reland] Post loading tasks on the appropriate WebFrameScheduler's queue

components/scheduler/child/web_task_runner_impl.cc

 // 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.
 
 #include "components/scheduler/child/web_task_runner_impl.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/single_thread_task_runner.h"
 #include "third_party/WebKit/public/platform/WebTraceLocation.h"
@@ skipping 29 matching lines @@
     const blink::WebTraceLocation& web_location,
     blink::WebTaskRunner::Task* task,
     double delayMs) {
   tracked_objects::Location location(web_location.functionName(),
                                      web_location.fileName(), -1, nullptr);
   task_runner_->PostDelayedTask(
       location, base::Bind(&blink::WebTaskRunner::Task::run, base::Owned(task)),
       base::TimeDelta::FromMillisecondsD(delayMs));
 }
 
+blink::WebTaskRunner* WebTaskRunnerImpl::clone() {
+  return new WebTaskRunnerImpl(task_runner_);
+}
+
 }  // namespace scheduler