[Reland] Per WebViewScheduler virtual time

components/scheduler/renderer/web_frame_scheduler_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/renderer/web_frame_scheduler_impl.h"
 
 #include "components/scheduler/base/real_time_domain.h"
 #include "components/scheduler/base/virtual_time_domain.h"
 #include "components/scheduler/child/web_task_runner_impl.h"
 #include "components/scheduler/renderer/auto_advancing_virtual_time_domain.h"
@@ skipping 108 matching lines @@
 
   if (loading_task_queue_) {
     loading_task_queue_->SetTimeDomain(
         parent_web_view_scheduler_->virtual_time_domain());
     loading_task_queue_->SetPumpPolicy(
         parent_web_view_scheduler_->GetVirtualTimePumpPolicy());
   }
 }
 
 void WebFrameSchedulerImpl::OnVirtualTimePumpPolicyChanged() {
+  DCHECK(parent_web_view_scheduler_);
   if (!parent_web_view_scheduler_->virtual_time_domain())
     return;
 
   if (timer_task_queue_) {
     timer_task_queue_->SetPumpPolicy(
         parent_web_view_scheduler_->GetVirtualTimePumpPolicy());
   }
 
   if (loading_task_queue_) {
     loading_task_queue_->SetPumpPolicy(
         parent_web_view_scheduler_->GetVirtualTimePumpPolicy());
   }
 }
 
 }  // namespace scheduler