Fix SkAtomics_win.h typos.

src/ports/SkAtomics_win.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkAtomics_win_DEFINED
 #define SkAtomics_win_DEFINED
 
@@ skipping 23 matching lines @@
     return _InterlockedDecrement(reinterpret_cast<long*>(addr)) + 1;
 }
 
 static inline void sk_membar_acquire__after_atomic_dec() { }
 
 static inline bool sk_atomic_cas(int32_t* addr, int32_t before, int32_t after) {
     return _InterlockedCompareExchange(reinterpret_cast<long*>(addr), after, before) == before;
 }
 
 static inline void* sk_atomic_cas(void** addr, void* before, void* after) {
-    return InterlockedCompareExchange(reinterpret_cast<long*>(addr), after, before);
+    return InterlockedCompareExchangePointer(addr, after, before);
 }
 
 static inline void sk_membar_acquire__after_atomic_conditional_inc() { }
 
 #endif