Fix TODO in SkMutex_win.h to prevent accidental copying.

src/ports/SkMutex_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 SkMutex_win_DEFINED
 #define SkMutex_win_DEFINED
 
@@ skipping 12 matching lines @@
 #
 #ifdef WIN32_IS_MEAN_WAS_LOCALLY_DEFINED
 #  undef WIN32_IS_MEAN_WAS_LOCALLY_DEFINED
 #  undef WIN32_LEAN_AND_MEAN
 #endif
 #ifdef NOMINMAX_WAS_LOCALLY_DEFINED
 #  undef NOMINMAX_WAS_LOCALLY_DEFINED
 #  undef NOMINMAX
 #endif
 
-// TODO: this exists because SK_DECLARE_STATIC_ONCE in methods is currently
-// relying on a compiler bug which allows the '=' to work.
-// All use of SK_DECLARE_STATIC_ONCE in methods is unsafe, and must be removed.
-// To find these cases, make SkMutex's copy and assignement private directly.
-class SkNoncopyableMutex {
-public:
-    SkNoncopyableMutex() { }
-
-private:
-    SkNoncopyableMutex(const SkNoncopyableMutex&);
-    SkNoncopyableMutex& operator=(const SkNoncopyableMutex&);
-};
-
 // On Windows, SkBaseMutex and SkMutex are the same thing,
 // we can't easily get rid of static initializers.
-class SkMutex : SkNoncopyableMutex {
+class SkMutex {
 public:
     SkMutex() {
         InitializeCriticalSection(&fStorage);
     }
 
     ~SkMutex() {
         DeleteCriticalSection(&fStorage);
     }
 
     void acquire() {
         EnterCriticalSection(&fStorage);
     }
 
     void release() {
         LeaveCriticalSection(&fStorage);
     }
 
 private:
+    SkMutex(const SkMutex&);
+    SkMutex& operator=(const SkMutex&);
+
     CRITICAL_SECTION fStorage;
 };
 
 typedef SkMutex SkBaseMutex;
 
 // Windows currently provides no documented means of POD initializing a CRITICAL_SECTION.
 #define SK_DECLARE_STATIC_MUTEX(name) static SkBaseMutex name
 #define SK_DECLARE_GLOBAL_MUTEX(name) SkBaseMutex name
 
 #endif