JPEGImageDecoder RGB565 and downsample support and related Skia imagegenerator changes

third_party/WebKit/Source/platform/image-decoders/jpeg/JPEGImageDecoder.h

 /*
  * Copyright (C) 2006 Apple Computer, Inc.  All rights reserved.
  * Copyright (C) 2008-2009 Torch Mobile, Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 36 matching lines @@
     String filenameExtension() const override { return "jpg"; }
     void onSetData(SharedBuffer* data) override;
     bool hasColorProfile() const override { return m_hasColorProfile; }
     IntSize decodedSize() const override { return m_decodedSize; }
     IntSize decodedYUVSize(int component, SizeType) const override;
     bool setSize(unsigned width, unsigned height) override;
     bool canDecodeToYUV() override;
     bool decodeToYUV() override;
     void setImagePlanes(PassOwnPtr<ImagePlanes>) override;
     bool hasImagePlanes() const { return m_imagePlanes; }
+    void getAvailableDecodeAndScale(ImageFrame::ColorType* outType, float* scale, float* lowerScale) override;
+    bool activateDecodeAndScale(ImageFrame::ColorType outColor, size_t maxDecodedBytes = noDecodedImageByteLimit) override;
+    void disableDecodeAndScale() override;
+    bool decodeToRGB565Enabled() const { return (m_decodeColor == ImageFrame::RGB565); }
+    bool hasFramebufferChanged() const;
 
     bool outputScanlines();
     unsigned desiredScaleNumerator() const;
     void complete();
 
     void setOrientation(ImageOrientation orientation) { m_orientation = orientation; }
     void setHasColorProfile(bool hasColorProfile) { m_hasColorProfile = hasColorProfile; }
     void setDecodedSize(unsigned width, unsigned height);
 
 private:
     // ImageDecoder:
     void decodeSize() override { decode(true); }
     void decode(size_t) override { decode(false); }
 
     // Decodes the image.  If |onlySize| is true, stops decoding after
     // calculating the image size.  If decoding fails but there is no more
     // data coming, sets the "decode failure" flag.
     void decode(bool onlySize);
 
     OwnPtr<JPEGImageReader> m_reader;
     OwnPtr<ImagePlanes> m_imagePlanes;
     IntSize m_decodedSize;
     bool m_hasColorProfile;
+    ImageFrame::ColorType m_decodeColor;
+    // keep the value to restore after disableDecodeAndScale()
+    size_t m_originalMaxDecodedBytes;
 };
 
 } // namespace blink
 
 #endif