diff -r 000000000000 -r 6474c204b198 gfx/skia/trunk/src/lazy/SkCachingPixelRef.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/skia/trunk/src/lazy/SkCachingPixelRef.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,69 @@
+/*
+ * 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 "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
+ *  or be destroyed before the next lock.  If so, onLockPixels will
+ *  attempt to re-decode.
+ *
+ *  Decoding is handled by the SkImageGenerator
+ */
+class SkCachingPixelRef : public SkPixelRef {
+public:
+    SK_DECLARE_INST_COUNT(SkCachingPixelRef)
+    /**
+     *  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 Install fails or when the SkCachingPixelRef that is
+     *  installed into destination is destroyed, it will call
+     *  SkDELETE() on the generator.  Therefore, generator should be
+     *  allocated with SkNEW() or SkNEW_ARGS().
+     */
+    static bool Install(SkImageGenerator* gen, SkBitmap* dst);
+
+protected:
+    virtual ~SkCachingPixelRef();
+    virtual bool onNewLockPixels(LockRec*) SK_OVERRIDE;
+    virtual void onUnlockPixels() SK_OVERRIDE;
+    virtual bool onLockPixelsAreWritable() const SK_OVERRIDE { return false; }
+
+    virtual SkData* onRefEncodedData() SK_OVERRIDE {
+        return fImageGenerator->refEncodedData();
+    }
+    // No need to flatten this object. When flattening an SkBitmap,
+    // SkWriteBuffer will check the encoded data and write that
+    // instead.
+    // Future implementations of SkWriteBuffer will need to
+    // special case for onRefEncodedData as well.
+    SK_DECLARE_UNFLATTENABLE_OBJECT()
+
+private:
+    SkImageGenerator* const fImageGenerator;
+    bool                    fErrorInDecoding;
+    void*                   fScaledCacheId;
+    const size_t            fRowBytes;
+
+    SkCachingPixelRef(const SkImageInfo&, SkImageGenerator*, size_t rowBytes);
+
+    typedef SkPixelRef INHERITED;
+};
+
+#endif  // SkCachingPixelRef_DEFINED