Introduce a basic Blink Scheduler

Source/web/WebKit.cpp

Index: Source/web/WebKit.cpp
diff --git a/Source/web/WebKit.cpp b/Source/web/WebKit.cpp
index 16809ed4767079b4b01f4db1237e17ba5d5b048c..2584fd6f183e960e477a2aecd1e878fae5566277 100644
--- a/Source/web/WebKit.cpp
+++ b/Source/web/WebKit.cpp
@@ -50,6 +50,7 @@
 #include "platform/heap/Heap.h"
 #include "platform/heap/glue/MessageLoopInterruptor.h"
 #include "platform/heap/glue/PendingGCRunner.h"
+#include "platform/scheduler/Scheduler.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebPrerenderingSupport.h"
 #include "public/platform/WebThread.h"
@@ -173,6 +174,7 @@ void initializeWithoutV8(Platform* platform)
         s_messageLoopInterruptor = new WebCore::MessageLoopInterruptor(currentThread);
         WebCore::ThreadState::current()->addInterruptor(s_messageLoopInterruptor);
     }
+    WebCore::Scheduler::initializeOnMainThread();
 
     DEFINE_STATIC_LOCAL(WebCore::ModulesInitializer, initializer, ());
     initializer.init();
@@ -203,6 +205,7 @@ void shutdown()
 
     ASSERT(s_isolateInterruptor);
     WebCore::ThreadState::current()->removeInterruptor(s_isolateInterruptor);
+    WebCore::Scheduler::shutdown();
 
     // currentThread will always be non-null in production, but can be null in Chromium unit tests.
     if (Platform::current()->currentThread()) {