TSAN: use somewhat pithier SK_ANNOTATE_UNPROTECTED_READ.

include/core/SkRefCnt.h

Index: include/core/SkRefCnt.h
diff --git a/include/core/SkRefCnt.h b/include/core/SkRefCnt.h
index 28591920a68ba5dc167f44dd3507c3a5ec783648..e4524beff7aed72e346b6289e25525c0e8a14ba0 100644
--- a/include/core/SkRefCnt.h
+++ b/include/core/SkRefCnt.h
@@ -10,6 +10,7 @@
 #ifndef SkRefCnt_DEFINED
 #define SkRefCnt_DEFINED
 
+#include "SkDynamicAnnotations.h"
 #include "SkThread.h"
 #include "SkInstCnt.h"
 #include "SkTemplates.h"
@@ -44,11 +45,13 @@ public:
     /** Return the reference count. Use only for debugging. */
     int32_t getRefCnt() const { return fRefCnt; }
 
-    /** Returns true if the caller is the only owner.
+    /** May return true if the caller is the only owner.
      *  Ensures that all previous owner's actions are complete.
      */
     bool unique() const {
-        bool const unique = (1 == fRefCnt);
+        // We believe we're reading fRefCnt in a safe way here, so we stifle the TSAN warning about
+        // an unproctected read.  Generally, don't read fRefCnt, and don't stifle this warning.

[bungeman-skia, 2014/02/04 17:21:39]

nit: two spaces after the period.

+        bool const unique = (1 == SK_ANNOTATE_UNPROTECTED_READ(fRefCnt));
         if (unique) {
             // Acquire barrier (L/SL), if not provided by load of fRefCnt.
             // Prevents user's 'unique' code from happening before decrements.