diff -r 000000000000 -r 6474c204b198 gfx/skia/trunk/src/core/SkTLS.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/skia/trunk/src/core/SkTLS.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,84 @@
+//
+//  SkTLS.h
+//
+//
+//  Created by Mike Reed on 4/21/12.
+//  Copyright (c) 2012 __MyCompanyName__. All rights reserved.
+//
+
+#ifndef SkTLS_DEFINED
+#define SkTLS_DEFINED
+
+#include "SkTypes.h"
+
+/**
+ *  Maintains a per-thread cache, using a CreateProc as the key into that cache.
+ */
+class SkTLS {
+public:
+    typedef void* (*CreateProc)();
+    typedef void  (*DeleteProc)(void*);
+
+    /**
+     *  If Get() has previously been called with this CreateProc, then this
+     *  returns its cached data, otherwise it returns NULL. The CreateProc is
+     *  never invoked in Find, it is only used as a key for searching the
+     *  cache.
+     */
+    static void* Find(CreateProc);
+
+    /**
+     *  Return the cached data that was returned by the CreateProc. This proc
+     *  is only called the first time Get is called, and there after it is
+     *  cached (per-thread), using the CreateProc as a key to look it up.
+     *
+     *  When this thread, or Delete is called, the cached data is removed, and
+     *  if a DeleteProc was specified, it is passed the pointer to the cached
+     *  data.
+     */
+    static void* Get(CreateProc, DeleteProc);
+
+    /**
+     *  Remove (optionally calling the DeleteProc if it was specificed in Get)
+     *  the cached data associated with this CreateProc. If no associated cached
+     *  data is found, do nothing.
+     */
+    static void Delete(CreateProc);
+
+private:
+    // Our implementation requires only 1 TLS slot, as we manage multiple values
+    // ourselves in a list, with the platform specific value as our head.
+
+    /**
+     *  Implemented by the platform, to return the value of our (one) slot per-thread
+     *
+     *  If forceCreateTheSlot is true, then we must have created the "slot" for
+     *  our TLS, even though we know that the return value will be NULL in that
+     *  case (i.e. no-slot and first-time-slot both return NULL). This ensures
+     *  that after calling GetSpecific, we know that we can legally call
+     *  SetSpecific.
+     *
+     *  If forceCreateTheSlot is false, then the impl can either create the
+     *  slot or not.
+     */
+    static void* PlatformGetSpecific(bool forceCreateTheSlot);
+
+    /**
+     *  Implemented by the platform, to set the value for our (one) slot per-thread
+     *
+     *  The implementation can rely on GetSpecific(true) having been previously
+     *  called before SetSpecific is called.
+     */
+    static void  PlatformSetSpecific(void*);
+
+public:
+    /**
+     *  Will delete our internal list. To be called by the platform if/when its
+     *  TLS slot is deleted (often at thread shutdown).
+     *
+     *  Public *only* for the platform's use, not to be called by a client.
+     */
+    static void Destructor(void* ptr);
+};
+
+#endif