Add SkEncodedInfo to report properties of encoded image data

src/codec/SkWebpCodec.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkWebpCodec_DEFINED
 #define SkWebpCodec_DEFINED
 
@@ skipping 16 matching lines @@
     Result onGetPixels(const SkImageInfo&, void*, size_t, const Options&, SkPMColor*, int*, int*)
             override;
     SkEncodedFormat onGetEncodedFormat() const override { return kWEBP_SkEncodedFormat; }
 
     SkISize onGetScaledDimensions(float desiredScale) const override;
 
     bool onDimensionsSupported(const SkISize&) override;
 
     bool onGetValidSubset(SkIRect* /* desiredSubset */) const override;
 private:
-    SkWebpCodec(const SkImageInfo&, SkStream*);
+    SkWebpCodec(int width, int height, const SkEncodedInfo&, SkStream*);
 
     typedef SkCodec INHERITED;
 };
 #endif // SkWebpCodec_DEFINED