retool image cache to be generic cache

src/lazy/SkCachingPixelRef.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 SkCachingPixelRef_DEFINED
 #define SkCachingPixelRef_DEFINED
 
+#include "SkBitmapCache.h"
 #include "SkImageInfo.h"
 #include "SkImageGenerator.h"
 #include "SkPixelRef.h"
 
 class SkColorTable;
 
 /**
  *  PixelRef which defers decoding until SkBitmap::lockPixels() is
  *  called.  Caches the decoded images in the global
  *  SkScaledImageCache.  When the pixels are unlocked, this cache may
@@ skipping 24 matching lines @@
     virtual void onUnlockPixels() SK_OVERRIDE;
     virtual bool onLockPixelsAreWritable() const SK_OVERRIDE { return false; }
 
     virtual SkData* onRefEncodedData() SK_OVERRIDE {
         return fImageGenerator->refEncodedData();
     }
 
 private:
     SkImageGenerator* const fImageGenerator;
     bool                    fErrorInDecoding;
-    void*                   fScaledCacheId;
     const size_t            fRowBytes;
 
+    SkBitmap                fLockedBitmap;
+
     SkCachingPixelRef(const SkImageInfo&, SkImageGenerator*, size_t rowBytes);
 
     typedef SkPixelRef INHERITED;
 };
 
 #endif  // SkCachingPixelRef_DEFINED