Use the scheduling mechanism provided by the platform

Source/web/WebKit.cpp

Index: Source/web/WebKit.cpp
diff --git a/Source/web/WebKit.cpp b/Source/web/WebKit.cpp
index eb629d06338d4382a58b4af0b20595cf6b897b5d..869d9090b4924bb13e17e97992e874abcc5b2af4 100644
--- a/Source/web/WebKit.cpp
+++ b/Source/web/WebKit.cpp
@@ -50,9 +50,9 @@
 #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/WebScheduler.h"
 #include "public/platform/WebThread.h"
 #include "web/IndexedDBClientImpl.h"
 #include "web/WebMediaPlayerClientImpl.h"
@@ -132,7 +132,7 @@ static void cryptographicallyRandomValues(unsigned char* buffer, size_t length)
 
 static void callOnMainThreadFunction(WTF::MainThreadFunction function, void* context)
 {
-    Scheduler::shared()->postTask(FROM_HERE, bind(function, context));
+    Platform::current()->callOnMainThread(function, context);
 }
 
 void initializeWithoutV8(Platform* platform)
@@ -147,7 +147,6 @@ void initializeWithoutV8(Platform* platform)
     WTF::initialize(currentTimeFunction, monotonicallyIncreasingTimeFunction);
     WTF::initializeMainThread(callOnMainThreadFunction);
     Heap::init();
-    Scheduler::initializeOnMainThread();
 
     ThreadState::attachMainThread();
     // currentThread will always be non-null in production, but can be null in Chromium unit tests.
@@ -220,7 +219,8 @@ void shutdownWithoutV8()
 {
     ASSERT(!s_endOfTaskRunner);
     CoreInitializer::shutdown();
-    Scheduler::shutdown();
+    if (WebScheduler* scheduler = Platform::current()->scheduler())
+        scheduler->shutdown();
     Heap::shutdown();
     WTF::shutdown();
     Platform::shutdown();