Fast path for ThreadSpecific for main thread on TLS-slow platforms

third_party/WebKit/Source/wtf/ThreadingPthreads.cpp

Index: third_party/WebKit/Source/wtf/ThreadingPthreads.cpp
diff --git a/third_party/WebKit/Source/wtf/ThreadingPthreads.cpp b/third_party/WebKit/Source/wtf/ThreadingPthreads.cpp
index ad9b520ac9f44add1284c67ea911ffe9aed00030..5cb42578f75b6390e9e352239a15bffeb2f91edc 100644
--- a/third_party/WebKit/Source/wtf/ThreadingPthreads.cpp
+++ b/third_party/WebKit/Source/wtf/ThreadingPthreads.cpp
@@ -80,13 +80,13 @@ static Mutex* atomicallyInitializedStaticMutex;
 void initializeThreading() {
   // This should only be called once.
   DCHECK(!atomicallyInitializedStaticMutex);
+  WTFThreadData::initialize();
 
   // StringImpl::empty() does not construct its static string in a threadsafe
   // fashion, so ensure it has been initialized from here.
   StringImpl::empty();
   StringImpl::empty16Bit();
   atomicallyInitializedStaticMutex = new Mutex;
-  wtfThreadData();
   initializeDates();
   // Force initialization of static DoubleToStringConverter converter variable
   // inside EcmaScriptConverter function while we are in single thread mode.
@@ -103,15 +103,7 @@ void unlockAtomicallyInitializedStaticMutex() {
 }
 
 ThreadIdentifier currentThread() {
-// TLS lookup is fast on these platforms.
-#if defined(__GLIBC__) || OS(ANDROID) || OS(FREEBSD)
-  return wtfThreadData().threadId();
-#else
-  // TODO(csharrison): For platforms where TLS lookup is slow, use the hack that
-  // oilpan uses in ThreadState::current() to check if this is the main thread
-  // via stack address.
-  return internal::currentThreadSyscall();
-#endif
+  return WTFThreadData::current().threadId();
 }
 
 MutexBase::MutexBase(bool recursive) {