Refactor TimeBase to post tasks. Workers to use real Idle tasks.

Source/core/Init.cpp

Index: Source/core/Init.cpp
diff --git a/Source/core/Init.cpp b/Source/core/Init.cpp
index 11b27d357b054e72178949581c0a9ee71a31cafd..c16ea897f62bacebdb277f18506ac0f60fc2a42f 100644
--- a/Source/core/Init.cpp
+++ b/Source/core/Init.cpp
@@ -55,7 +55,6 @@
 #include "platform/EventTracer.h"
 #include "platform/FontFamilyNames.h"
 #include "platform/Partitions.h"
-#include "platform/PlatformThreadData.h"
 #include "platform/weborigin/KURL.h"
 #include "wtf/text/StringStatics.h"
 
@@ -109,10 +108,6 @@ void CoreInitializer::init()
 
     registerEventFactory();
 
-    // Ensure that the main thread's thread-local data is initialized before
-    // starting any worker threads.
-    PlatformThreadData::current();
-
     StringImpl::freezeStaticStrings();
 
     // Creates HTMLParserThread::shared and ScriptStreamerThread::shared, but