Introduce WebTaskRunner Patch 3/5

Source/core/dom/MainThreadTaskRunner.cpp

Index: Source/core/dom/MainThreadTaskRunner.cpp
diff --git a/Source/core/dom/MainThreadTaskRunner.cpp b/Source/core/dom/MainThreadTaskRunner.cpp
index 58b45ab0306a35c4fc0da010a74589f8ef4887aa..5b03526c3ad2f7f5eab3ab069e0c951f9d0a9a39 100644
--- a/Source/core/dom/MainThreadTaskRunner.cpp
+++ b/Source/core/dom/MainThreadTaskRunner.cpp
@@ -35,7 +35,7 @@
 
 namespace blink {
 
-class MainThreadTask : public WebThread::Task {
+class MainThreadTask : public WebTaskRunner::Task {
     WTF_MAKE_NONCOPYABLE(MainThreadTask); WTF_MAKE_FAST_ALLOCATED(MainThreadTask);
 public:
     MainThreadTask(WeakPtrWillBeRawPtr<MainThreadTaskRunner> runner, PassOwnPtr<ExecutionContextTask> task, bool isInspectorTask)
@@ -85,12 +85,12 @@ void MainThreadTaskRunner::postTask(const WebTraceLocation& location, PassOwnPtr
 {
     if (!task->taskNameForInstrumentation().isEmpty())
         InspectorInstrumentation::didPostExecutionContextTask(m_context, task.get());
-    Platform::current()->mainThread()->postTask(location, new MainThreadTask(createWeakPointerToSelf(), task, false));
+    Platform::current()->mainThread()->defaultTaskRunner()->postTask(location, new MainThreadTask(createWeakPointerToSelf(), task, false));
 }
 
 void MainThreadTaskRunner::postInspectorTask(const WebTraceLocation& location, PassOwnPtr<ExecutionContextTask> task)
 {
-    Platform::current()->mainThread()->postTask(location, new MainThreadTask(createWeakPointerToSelf(), task, true));
+    Platform::current()->mainThread()->defaultTaskRunner()->postTask(location, new MainThreadTask(createWeakPointerToSelf(), task, true));
 }
 
 void MainThreadTaskRunner::perform(PassOwnPtr<ExecutionContextTask> task, bool isInspectorTask)