hide discardable factory from public imagegenerator api

include/core/SkImageGenerator.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 SkImageGenerator_DEFINED
 #define SkImageGenerator_DEFINED
 
-#include "SkDiscardableMemory.h"
 #include "SkImageInfo.h"
 
 class SkBitmap;
 class SkData;
 class SkImageGenerator;
 
 /**
  *  Takes ownership of SkImageGenerator.  If this method fails for
  *  whatever reason, it will return false and immediatetely delete
  *  the generator.  If it succeeds, it will modify destination
  *  bitmap.
  *
  *  If generator is NULL, will safely return false.
  *
  *  If this fails or when the SkDiscardablePixelRef that is
  *  installed into destination is destroyed, it will call
  *  SkDELETE() on the generator.  Therefore, generator should be
  *  allocated with SkNEW() or SkNEW_ARGS().
  *
  *  @param destination Upon success, this bitmap will be
  *  configured and have a pixelref installed.
  *
- *  @param factory If not NULL, this object will be used as a
- *  source of discardable memory when decoding.  If NULL, then
- *  SkDiscardableMemory::Create() will be called.
- *
  *  @return true iff successful.
  */
-SK_API bool SkInstallDiscardablePixelRef(SkImageGenerator* generator,
-                                         SkBitmap* destination,
-                                         SkDiscardableMemory::Factory* factory = NULL);
+SK_API bool SkInstallDiscardablePixelRef(SkImageGenerator*, SkBitmap* destination);
 
 
 /**
  *  An interface that allows a purgeable PixelRef (such as a
  *  SkDiscardablePixelRef) to decode and re-decode an image as needed.
  */
 class SK_API SkImageGenerator {
 public:
     /**
      *  The PixelRef which takes ownership of this SkImageGenerator
@@ skipping 39 matching lines @@
      *
      *  @return false if anything goes wrong or if the image info is
      *          unsupported.
      */
     virtual bool getPixels(const SkImageInfo& info,
                            void* pixels,
                            size_t rowBytes) = 0;
 };
 
 #endif  // SkImageGenerator_DEFINED