Revert "Revert "cache SkImage::Info calculation in lazypixelref""

src/lazy/SkLazyPixelRef.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkLazyPixelRef_DEFINED
 #define SkLazyPixelRef_DEFINED
 
@@ skipping 53 matching lines @@
     virtual bool onImplementsDecodeInto() SK_OVERRIDE;
     virtual bool onDecodeInto(int pow2, SkBitmap*) SK_OVERRIDE;
 
 private:
     bool                        fErrorInDecoding;
     SkData*                     fData;
     SkBitmapFactory::DecodeProc fDecodeProc;
     SkImageCache*               fImageCache;
     intptr_t                    fCacheId;
     size_t                      fRowBytes;
+    SkImage::Info               fLazilyCachedInfo;
 
 #if LAZY_CACHE_STATS
     static int32_t              gCacheHits;
     static int32_t              gCacheMisses;
 #endif
 
+    // lazily initialized our cached info. Returns NULL on failure.
+    const SkImage::Info* getCachedInfo();
+
     typedef SkPixelRef INHERITED;
 };
 
 #endif  // SkLazyPixelRef_DEFINED