fAddedToCache doesn't need to be atomic.

include/core/SkPixelRef.h

 /*
  * Copyright 2008 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkPixelRef_DEFINED
 #define SkPixelRef_DEFINED
 
@@ skipping 230 matching lines @@
         virtual ~GenIDChangeListener() {}
         virtual void onChange() = 0;
     };
 
     // Takes ownership of listener.
     void addGenIDChangeListener(GenIDChangeListener* listener);
 
     // Call when this pixelref is part of the key to a resourcecache entry. This allows the cache
     // to know automatically those entries can be purged when this pixelref is changed or deleted.
     void notifyAddedToCache() {
-        fAddedToCache.store(true);
+        fAddedToCache = true;
     }
 
 protected:
     /**
      *  On success, returns true and fills out the LockRec for the pixels. On
      *  failure returns false and ignores the LockRec parameter.
      *
      *  The caller will have already acquired a mutex for thread safety, so this
      *  method need not do that.
      */
@@ skipping 52 matching lines @@
 
     // mostly const. fInfo.fAlpahType can be changed at runtime.
     const SkImageInfo fInfo;
 
     // LockRec is only valid if we're in a locked state (isLocked())
     LockRec         fRec;
     int             fLockCount;
 
     mutable SkAtomic<uint32_t> fGenerationID;
     mutable SkAtomic<bool>     fUniqueGenerationID;
-    SkAtomic<bool>             fAddedToCache;
+    bool fAddedToCache;
 #ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
     const uint32_t fStableID;
 #endif
 
     SkTDArray<GenIDChangeListener*> fGenIDChangeListeners;  // pointers are owned
 
     SkString    fURI;
 
     // can go from false to true, but never from true to false
     bool    fIsImmutable;
@@ skipping 18 matching lines @@
     /**
      *  Allocate a new pixelref matching the specified ImageInfo, allocating
      *  the memory for the pixels. If the ImageInfo requires a ColorTable,
      *  the pixelref will ref() the colortable.
      *  On failure return NULL.
      */
     virtual SkPixelRef* create(const SkImageInfo&, size_t rowBytes, SkColorTable*) = 0;
 };
 
 #endif