[Reland] Per WebViewScheduler virtual time

components/scheduler/child/web_task_runner_impl.cc

Index: components/scheduler/child/web_task_runner_impl.cc
diff --git a/components/scheduler/child/web_task_runner_impl.cc b/components/scheduler/child/web_task_runner_impl.cc
index 49b5133b9ab033ba545844c97b00628226727521..d3ba45532e278a49f5acf70c52afef7024b61cac 100644
--- a/components/scheduler/child/web_task_runner_impl.cc
+++ b/components/scheduler/child/web_task_runner_impl.cc
@@ -7,6 +7,7 @@
 #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 {
@@ -40,6 +41,24 @@ void WebTaskRunnerImpl::postDelayedTask(
       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_);
 }