[Reland] Per WebViewScheduler virtual time

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 "components/scheduler/base/task_queue.h"
+#include "components/scheduler/base/time_domain.h"
 #include "third_party/WebKit/public/platform/WebTraceLocation.h"
 
 namespace scheduler {
 
 WebTaskRunnerImpl::WebTaskRunnerImpl(scoped_refptr<TaskQueue> task_queue)
     : task_queue_(task_queue) {}
 
 WebTaskRunnerImpl::~WebTaskRunnerImpl() {}
 
 void WebTaskRunnerImpl::postTask(const blink::WebTraceLocation& web_location,
@@ skipping 13 matching lines @@
   DCHECK_GE(delayMs, 0.0);
   tracked_objects::Location location(web_location.functionName(),
                                      web_location.fileName(), -1, nullptr);
   task_queue_->PostDelayedTask(
       location,
       base::Bind(&WebTaskRunnerImpl::runTask,
                  base::Passed(scoped_ptr<blink::WebTaskRunner::Task>(task))),
       base::TimeDelta::FromMillisecondsD(delayMs));
 }
 
+double WebTaskRunnerImpl::virtualTimeSeconds() const {
+  return (Now() - base::TimeTicks::UnixEpoch()).InSecondsF();
+}
+
+double WebTaskRunnerImpl::monotonicallyIncreasingVirtualTimeSeconds() const {
+  return Now().ToInternalValue() /
+         static_cast<double>(base::Time::kMicrosecondsPerSecond);
+}
+
+base::TimeTicks WebTaskRunnerImpl::Now() const {
+  TimeDomain* time_domain = task_queue_->GetTimeDomain();
+  // It's possible task_queue_ has been Unregistered which can lead to a null
+  // TimeDomain.  If that happens just return the current real time.
+  if (!time_domain)
+    return base::TimeTicks::Now();
+  return time_domain->Now();
+}
+
 blink::WebTaskRunner* WebTaskRunnerImpl::clone() {
   return new WebTaskRunnerImpl(task_queue_);
 }
 
 void WebTaskRunnerImpl::runTask(scoped_ptr<blink::WebTaskRunner::Task> task)
 {
   task->run();
 }
 
 }  // namespace scheduler