Split TLS implementation into its own translation unit.

src/ports/SkTLS_none.cpp

Index: src/ports/SkTLS_none.cpp
===================================================================
--- src/ports/SkTLS_none.cpp	(revision 0)
+++ src/ports/SkTLS_none.cpp	(working copy)
@@ -0,0 +1,18 @@
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkTLS.h"
+
+static void* gSpecific = NULL;
+
+void* SkTLS::PlatformGetSpecific(bool) {
+    return gSpecific;
+}
+
+void SkTLS::PlatformSetSpecific(void* ptr) {
+    gSpecific = ptr;
+}