Make WebTaskRunner ThreadSafeRefCounted

third_party/WebKit/Source/platform/scheduler/child/web_task_runner_impl.cc

Index: third_party/WebKit/Source/platform/scheduler/child/web_task_runner_impl.cc
diff --git a/third_party/WebKit/Source/platform/scheduler/child/web_task_runner_impl.cc b/third_party/WebKit/Source/platform/scheduler/child/web_task_runner_impl.cc
index 5d8d6c445338ded676fc6cdba92cc9db30a98545..e2dc0e49675a2b27f22bcc04b0c84cbc50f981d8 100644
--- a/third_party/WebKit/Source/platform/scheduler/child/web_task_runner_impl.cc
+++ b/third_party/WebKit/Source/platform/scheduler/child/web_task_runner_impl.cc
@@ -14,10 +14,10 @@
 namespace blink {
 namespace scheduler {
 
-WebTaskRunnerImpl::WebTaskRunnerImpl(scoped_refptr<TaskQueue> task_queue)
-    : task_queue_(task_queue) {}
-
-WebTaskRunnerImpl::~WebTaskRunnerImpl() {}
+RefPtr<WebTaskRunnerImpl> WebTaskRunnerImpl::create(
+    scoped_refptr<TaskQueue> task_queue) {
+  return adoptRef(new WebTaskRunnerImpl(std::move(task_queue)));
+}
 
 void WebTaskRunnerImpl::postDelayedTask(const WebTraceLocation& location,
                                         const base::Closure& task,
@@ -41,6 +41,11 @@ double WebTaskRunnerImpl::monotonicallyIncreasingVirtualTimeSeconds() const {
          static_cast<double>(base::Time::kMicrosecondsPerSecond);
 }
 
+WebTaskRunnerImpl::WebTaskRunnerImpl(scoped_refptr<TaskQueue> task_queue)
+    : task_queue_(std::move(task_queue)) {}
+
+WebTaskRunnerImpl::~WebTaskRunnerImpl() {}
+
 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
@@ -50,10 +55,6 @@ base::TimeTicks WebTaskRunnerImpl::Now() const {
   return time_domain->Now();
 }
 
-std::unique_ptr<blink::WebTaskRunner> WebTaskRunnerImpl::clone() {
-  return base::WrapUnique(new WebTaskRunnerImpl(task_queue_));
-}
-
 base::SingleThreadTaskRunner* WebTaskRunnerImpl::toSingleThreadTaskRunner() {
   return task_queue_.get();
 }