Reland of Worker: Introduce per-global-scope task scheduler

third_party/WebKit/Source/web/WebSharedWorkerImpl.cpp

Index: third_party/WebKit/Source/web/WebSharedWorkerImpl.cpp
diff --git a/third_party/WebKit/Source/web/WebSharedWorkerImpl.cpp b/third_party/WebKit/Source/web/WebSharedWorkerImpl.cpp
index 9f0e0963d6edaa02f0cde45b4c88bd069791d8ba..1f87bc26c29d592380909710fa12cafb802856be 100644
--- a/third_party/WebKit/Source/web/WebSharedWorkerImpl.cpp
+++ b/third_party/WebKit/Source/web/WebSharedWorkerImpl.cpp
@@ -32,6 +32,7 @@
 
 #include <memory>
 #include "core/dom/Document.h"
+#include "core/dom/TaskRunnerHelper.h"
 #include "core/events/MessageEvent.h"
 #include "core/inspector/ConsoleMessage.h"
 #include "core/loader/FrameLoadRequest.h"
@@ -254,7 +255,8 @@
     const WebTraceLocation& location,
     std::unique_ptr<WTF::CrossThreadClosure> task) {
   DCHECK(IsMainThread());
-  worker_thread_->PostTask(location, std::move(task));
+  TaskRunnerHelper::Get(TaskType::kNetworking, GetWorkerThread())
+      ->PostTask(location, std::move(task));
 }
 
 ThreadableLoadingContext* WebSharedWorkerImpl::GetThreadableLoadingContext() {
@@ -268,11 +270,12 @@
 void WebSharedWorkerImpl::Connect(
     std::unique_ptr<WebMessagePortChannel> web_channel) {
   DCHECK(IsMainThread());
-  GetWorkerThread()->PostTask(
-      BLINK_FROM_HERE,
-      CrossThreadBind(&WebSharedWorkerImpl::ConnectTaskOnWorkerThread,
-                      WTF::CrossThreadUnretained(this),
-                      WTF::Passed(std::move(web_channel))));
+  TaskRunnerHelper::Get(TaskType::kDOMManipulation, GetWorkerThread())
+      ->PostTask(
+          BLINK_FROM_HERE,
+          CrossThreadBind(&WebSharedWorkerImpl::ConnectTaskOnWorkerThread,
+                          WTF::CrossThreadUnretained(this),
+                          WTF::Passed(std::move(web_channel))));
 }
 
 void WebSharedWorkerImpl::ConnectTaskOnWorkerThread(