Move the thread local functions to the Thread class in runtime/platform

runtime/vm/isolate_win.cc

-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-#include "vm/isolate.h"
-
-#include "platform/assert.h"
-#include "vm/globals.h"
-
-namespace dart {
-
-DWORD isolate_key = TLS_OUT_OF_INDEXES;
-
-
-void Isolate::SetCurrent(Isolate* current) {
-  ASSERT(isolate_key != TLS_OUT_OF_INDEXES);
-  BOOL result = TlsSetValue(isolate_key, current);
-  if (!result) {
-    FATAL("TlsSetValue failed");
-  }
-}
-
-
-void Isolate::InitOnce() {
-  ASSERT(isolate_key == TLS_OUT_OF_INDEXES);
-  isolate_key = TlsAlloc();
-  if (isolate_key == TLS_OUT_OF_INDEXES) {
-    FATAL("TlsAlloc failed");
-  }
-  create_callback_ = NULL;
-}
-
-}  // namespace dart