SkImage method for detecting lazy decoding

src/lazy/SkDiscardablePixelRef.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 SkDiscardablePixelRef_DEFINED
 #define SkDiscardablePixelRef_DEFINED
 
@@ skipping 18 matching lines @@
     ~SkDiscardablePixelRef();
 
     bool onNewLockPixels(LockRec*) override;
     void onUnlockPixels() override;
     bool onLockPixelsAreWritable() const override { return false; }
 
     SkData* onRefEncodedData() override {
         return fGenerator->refEncodedData();
     }
 
+    bool onIsLazyGenerated() const override { return true; }
+
 private:
     SkImageGenerator* const fGenerator;
     SkDiscardableMemory::Factory* const fDMFactory;
     const size_t fRowBytes;
     // These const members should not change over the life of the
     // PixelRef, since the SkBitmap doesn't expect them to change.
 
     SkDiscardableMemory* fDiscardableMemory;
     bool                 fDiscardableMemoryIsLocked;
     SkAutoTUnref<SkColorTable> fCTable;
@@ skipping 15 matching lines @@
         return fGenerator->getYUV8Planes(sizes, planes, rowBytes, colorSpace);
     }
 
     friend bool SkInstallDiscardablePixelRef(SkImageGenerator*, const SkIRect*, SkBitmap*,
                                              SkDiscardableMemory::Factory*);
 
     typedef SkPixelRef INHERITED;
 };
 
 #endif  // SkDiscardablePixelRef_DEFINED