TSAN: use somewhat pithier SK_ANNOTATE_UNPROTECTED_READ.

include/core/SkOnce.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 SkOnce_DEFINED
 #define SkOnce_DEFINED
 
@@ skipping 10 matching lines @@
 //     SK_DECLARE_STATIC_ONCE(once);
 //     SkOnce(&once, set_up_my_singleton, &singleton);
 //     SkASSERT(NULL != singleton);
 //     return *singleton;
 // }
 //
 // OnceTest.cpp also should serve as a few other simple examples.
 //
 // You may optionally pass SkOnce a second function to be called at exit for cleanup.
 
+#include "SkDynamicAnnotations.h"
 #include "SkThread.h"
 #include "SkTypes.h"
 
 #define SK_ONCE_INIT { false, { 0, SkDEBUGCODE(0) } }
 #define SK_DECLARE_STATIC_ONCE(name) static SkOnceFlag name = SK_ONCE_INIT
 
 struct SkOnceFlag;  // If manually created, initialize with SkOnceFlag once = SK_ONCE_INIT
 
 template <typename Func, typename Arg>
 inline void SkOnce(SkOnceFlag* once, Func f, Arg arg, void(*atExit)() = NULL);
@@ skipping 67 matching lines @@
         // In version control terms this is like saying, "check in the work up
         // to and including f(arg), then check in *done=true as a subsequent change".
         //
         // We'll use this in the fast path to make sure f(arg)'s effects are
         // observable whenever we observe *done == true.
         release_barrier();
         once->done = true;
     }
 }
 
-// We nabbed this code from the dynamic_annotations library, and in their honor
-// we check the same define.  If you find yourself wanting more than just
-// SK_ANNOTATE_BENIGN_RACE, it might make sense to pull that in as a dependency
-// rather than continue to reproduce it here.
-
-#if DYNAMIC_ANNOTATIONS_ENABLED
-// TSAN provides this hook to supress a known-safe apparent race.
-extern "C" {
-void AnnotateBenignRace(const char* file, int line, const volatile void* mem, const char* desc);
-}
-#define SK_ANNOTATE_BENIGN_RACE(mem, desc) AnnotateBenignRace(__FILE__, __LINE__, mem, desc)
-#else
-#define SK_ANNOTATE_BENIGN_RACE(mem, desc)
-#endif
-
 // This is our fast path, called all the time.  We do really want it to be inlined.
 template <typename Func, typename Arg>
 inline void SkOnce(SkOnceFlag* once, Func f, Arg arg, void(*atExit)()) {
-    SK_ANNOTATE_BENIGN_RACE(&(once->done), "Don't worry TSAN, we're sure this is safe.");
-    if (!once->done) {
+    if (!SK_ANNOTATE_UNPROTECTED_READ(once->done)) {
         sk_once_slow(once, f, arg, atExit);
     }
     // Also known as a load-load/load-store barrier, this acquire barrier makes
     // sure that anything we read from memory---in particular, memory written by
     // calling f(arg)---is at least as current as the value we read from once->done.
     //
     // In version control terms, this is a lot like saying "sync up to the
     // commit where we wrote once->done = true".
     //
     // The release barrier in sk_once_slow guaranteed that once->done = true
     // happens after f(arg), so by syncing to once->done = true here we're
     // forcing ourselves to also wait until the effects of f(arg) are readble.
     acquire_barrier();
 }
 
 #undef SK_ANNOTATE_BENIGN_RACE
 
 #endif  // SkOnce_DEFINED