private iterator to visit all resource cache entries

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
 
 #include "SkAtomics.h"
 #include "SkBitmap.h"
 #include "SkFilterQuality.h"
 #include "SkImageInfo.h"
 #include "SkMutex.h"
 #include "SkPixmap.h"
 #include "SkRefCnt.h"
 #include "SkSize.h"
 #include "SkString.h"
 #include "SkTDArray.h"
 
 class SkColorTable;
 class SkData;
 struct SkIRect;
 
 class GrTexture;
+class SkDiscardableMemory;
 
 /** \class SkPixelRef
 
     This class is the smart container for pixel memory, and is used with
     SkBitmap. A pixelref is installed into a bitmap, and then the bitmap can
     access the actual pixel memory by calling lockPixels/unlockPixels.
 
     This class can be shared/accessed between multiple threads.
 */
 class SK_API SkPixelRef : public SkRefCnt {
@@ skipping 219 matching lines @@
 
     // 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);
     }
 
+    virtual SkDiscardableMemory* diagnostic_only_getDiscardable() const { return NULL; }
+
 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.
      */
     virtual bool onNewLockPixels(LockRec*) = 0;
 
@@ skipping 114 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