Delete SkImageDecoder

This image decoding implementation has been replaced
by SkCodec in Android.

Additionally, we have replaced uses of SkImageDecoder
in Skia and Google3 with uses of SkCodec.

Now we can delete SkImageDecoder :).

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1820503002
CQ_EXTRA_TRYBOTS=client.skia.compile:Build-Ubuntu-GCC-x86_64-Release-CMake-Trybot,Build-Mac-Clang-x86_64-Release-CMake-Trybot

Committed: https://skia.googlesource.com/skia/+/f799706656f2581c5bf5510d94df3fa17cce1607

Committed: https://skia.googlesource.com/skia/+/5b6e73e0c8282c4d85accbfbcecc6dee84f8a1eb

Committed: https://skia.googlesource.com/skia/+/f037fdebda2a2626e6512d7532063f2cd41a264d

Review URL: https://codereview.chromium.org/1820503002
diff --git a/src/images/SkImageDecoder_ktx.cpp b/src/images/SkImageDecoder_ktx.cpp
index 1566745..79f0293 100644
--- a/src/images/SkImageDecoder_ktx.cpp
+++ b/src/images/SkImageDecoder_ktx.cpp
@@ -6,10 +6,9 @@
  */
 
 #include "SkColorPriv.h"
-#include "SkImageDecoder.h"
+#include "SkImageEncoder.h"
 #include "SkImageGenerator.h"
 #include "SkPixelRef.h"
-#include "SkScaledBitmapSampler.h"
 #include "SkStream.h"
 #include "SkStreamPriv.h"
 #include "SkTypes.h"
@@ -17,230 +16,14 @@
 #include "ktx.h"
 #include "etc1.h"
 
-/////////////////////////////////////////////////////////////////////////////////////////
-
-
-/////////////////////////////////////////////////////////////////////////////////////////
-
-// KTX Image decoder
-// ---
-// KTX is a general texture data storage file format ratified by the Khronos Group. As an
-// overview, a KTX file contains all of the appropriate values needed to fully specify a
-// texture in an OpenGL application, including the use of compressed data.
-//
-// This decoder is meant to be used with an SkDiscardablePixelRef so that GPU backends
-// can sniff the data before creating a texture. If they encounter a compressed format
-// that they understand, they can then upload the data directly to the GPU. Otherwise,
-// they will decode the data into a format that Skia supports.
-
-class SkKTXImageDecoder : public SkImageDecoder {
-public:
-    SkKTXImageDecoder() { }
-
-    Format getFormat() const override {
-        return kKTX_Format;
-    }
-
-protected:
-    Result onDecode(SkStream* stream, SkBitmap* bm, Mode) override;
-
-private:
-    typedef SkImageDecoder INHERITED;
-};
-
-SkImageDecoder::Result SkKTXImageDecoder::onDecode(SkStream* stream, SkBitmap* bm, Mode mode) {
-    // TODO: Implement SkStream::copyToData() that's cheap for memory and file streams
-    auto data = SkCopyStreamToData(stream);
-    if (nullptr == data) {
-        return kFailure;
-    }
-
-    SkKTXFile ktxFile(data.get());
-    if (!ktxFile.valid()) {
-        return kFailure;
-    }
-
-    const unsigned short width = ktxFile.width();
-    const unsigned short height = ktxFile.height();
-
-    // Set a flag if our source is premultiplied alpha
-    const SkString premulKey("KTXPremultipliedAlpha");
-    const bool bSrcIsPremul = ktxFile.getValueForKey(premulKey) == SkString("True");
-
-    // Setup the sampler...
-    SkScaledBitmapSampler sampler(width, height, this->getSampleSize());
-
-    // Determine the alpha of the bitmap...
-    SkAlphaType alphaType = kOpaque_SkAlphaType;
-    if (ktxFile.isRGBA8()) {
-        if (this->getRequireUnpremultipliedColors()) {
-            alphaType = kUnpremul_SkAlphaType;
-            // If the client wants unpremul colors and we only have
-            // premul, then we cannot honor their wish.
-            if (bSrcIsPremul) {
-                return kFailure;
-            }
-        } else {
-            alphaType = kPremul_SkAlphaType;
-        }
-    }
-
-    // Search through the compressed formats to see if the KTX file is holding
-    // compressed data
-    bool ktxIsCompressed = false;
-    SkTextureCompressor::Format ktxCompressedFormat;
-    for (int i = 0; i < SkTextureCompressor::kFormatCnt; ++i) {
-        SkTextureCompressor::Format fmt = static_cast<SkTextureCompressor::Format>(i);
-        if (ktxFile.isCompressedFormat(fmt)) {
-            ktxIsCompressed = true;
-            ktxCompressedFormat = fmt;
-            break;
-        }
-    }
-
-    // If the compressed format is a grayscale image, then setup the bitmap properly...
-    bool isCompressedAlpha = ktxIsCompressed &&
-        ((SkTextureCompressor::kLATC_Format == ktxCompressedFormat) ||
-         (SkTextureCompressor::kR11_EAC_Format == ktxCompressedFormat));
-
-    // Set the image dimensions and underlying pixel type.
-    if (isCompressedAlpha) {
-        const int w = sampler.scaledWidth();
-        const int h = sampler.scaledHeight();
-        bm->setInfo(SkImageInfo::MakeA8(w, h));
-    } else {
-        const int w = sampler.scaledWidth();
-        const int h = sampler.scaledHeight();
-        bm->setInfo(SkImageInfo::MakeN32(w, h, alphaType));
-    }
-    
-    if (SkImageDecoder::kDecodeBounds_Mode == mode) {
-        return kSuccess;
-    }
-
-    // If we've made it this far, then we know how to grok the data.
-    if (!this->allocPixelRef(bm, nullptr)) {
-        return kFailure;
-    }
-
-    // Lock the pixels, since we're about to write to them...
-    SkAutoLockPixels alp(*bm);
-
-    if (isCompressedAlpha) {
-        if (!sampler.begin(bm, SkScaledBitmapSampler::kGray, *this)) {
-            return kFailure;
-        }
-
-        // Alpha data is only a single byte per pixel.
-        int nPixels = width * height;
-        SkAutoMalloc outRGBData(nPixels);
-        uint8_t *outRGBDataPtr = reinterpret_cast<uint8_t *>(outRGBData.get());
-
-        // Decode the compressed format
-        const uint8_t *buf = reinterpret_cast<const uint8_t *>(ktxFile.pixelData());
-        if (!SkTextureCompressor::DecompressBufferFromFormat(
-                outRGBDataPtr, width, buf, width, height, ktxCompressedFormat)) {
-            return kFailure;
-        }
-
-        // Set each of the pixels...
-        const int srcRowBytes = width;
-        const int dstHeight = sampler.scaledHeight();
-        const uint8_t *srcRow = reinterpret_cast<uint8_t *>(outRGBDataPtr);
-        srcRow += sampler.srcY0() * srcRowBytes;
-        for (int y = 0; y < dstHeight; ++y) {
-            sampler.next(srcRow);
-            srcRow += sampler.srcDY() * srcRowBytes;
-        }
-
-        return kSuccess;
-
-    } else if (ktxFile.isCompressedFormat(SkTextureCompressor::kETC1_Format)) {
-        if (!sampler.begin(bm, SkScaledBitmapSampler::kRGB, *this)) {
-            return kFailure;
-        }
-
-        // ETC1 Data is encoded as RGB pixels, so we should extract it as such
-        int nPixels = width * height;
-        SkAutoMalloc outRGBData(nPixels * 3);
-        uint8_t *outRGBDataPtr = reinterpret_cast<uint8_t *>(outRGBData.get());
-
-        // Decode ETC1
-        const uint8_t *buf = reinterpret_cast<const uint8_t *>(ktxFile.pixelData());
-        if (!SkTextureCompressor::DecompressBufferFromFormat(
-                outRGBDataPtr, width*3, buf, width, height, SkTextureCompressor::kETC1_Format)) {
-            return kFailure;
-        }
-
-        // Set each of the pixels...
-        const int srcRowBytes = width * 3;
-        const int dstHeight = sampler.scaledHeight();
-        const uint8_t *srcRow = reinterpret_cast<uint8_t *>(outRGBDataPtr);
-        srcRow += sampler.srcY0() * srcRowBytes;
-        for (int y = 0; y < dstHeight; ++y) {
-            sampler.next(srcRow);
-            srcRow += sampler.srcDY() * srcRowBytes;
-        }
-
-        return kSuccess;
-
-    } else if (ktxFile.isRGB8()) {
-
-        // Uncompressed RGB data (without alpha)
-        if (!sampler.begin(bm, SkScaledBitmapSampler::kRGB, *this)) {
-            return kFailure;
-        }
-
-        // Just need to read RGB pixels
-        const int srcRowBytes = width * 3;
-        const int dstHeight = sampler.scaledHeight();
-        const uint8_t *srcRow = reinterpret_cast<const uint8_t *>(ktxFile.pixelData());
-        srcRow += sampler.srcY0() * srcRowBytes;
-        for (int y = 0; y < dstHeight; ++y) {
-            sampler.next(srcRow);
-            srcRow += sampler.srcDY() * srcRowBytes;
-        }
-
-        return kSuccess;
-
-    } else if (ktxFile.isRGBA8()) {
-
-        // Uncompressed RGBA data
-
-        // If we know that the image contains premultiplied alpha, then
-        // we need to turn off the premultiplier
-        SkScaledBitmapSampler::Options opts (*this);
-        if (bSrcIsPremul) {
-            SkASSERT(bm->alphaType() == kPremul_SkAlphaType);
-            SkASSERT(!this->getRequireUnpremultipliedColors());
-
-            opts.fPremultiplyAlpha = false;
-        } 
-
-        if (!sampler.begin(bm, SkScaledBitmapSampler::kRGBA, opts)) {
-            return kFailure;
-        }
-
-        // Just need to read RGBA pixels
-        const int srcRowBytes = width * 4;
-        const int dstHeight = sampler.scaledHeight();
-        const uint8_t *srcRow = reinterpret_cast<const uint8_t *>(ktxFile.pixelData());
-        srcRow += sampler.srcY0() * srcRowBytes;
-        for (int y = 0; y < dstHeight; ++y) {
-            sampler.next(srcRow);
-            srcRow += sampler.srcDY() * srcRowBytes;
-        }
-
-        return kSuccess;
-    }
-
-    return kFailure;
-}
-
 ///////////////////////////////////////////////////////////////////////////////
 
 // KTX Image Encoder
 //
+// KTX is a general texture data storage file format ratified by the Khronos Group. As an
+// overview, a KTX file contains all of the appropriate values needed to fully specify a
+// texture in an OpenGL application, including the use of compressed data.
+//
 // This encoder takes a best guess at how to encode the bitmap passed to it. If
 // there is an installed discardable pixel ref with existing PKM data, then we
 // will repurpose the existing ETC1 data into a KTX file. If the data contains
@@ -304,28 +87,11 @@
 }
 
 /////////////////////////////////////////////////////////////////////////////////////////
-DEFINE_DECODER_CREATOR(KTXImageDecoder);
 DEFINE_ENCODER_CREATOR(KTXImageEncoder);
 /////////////////////////////////////////////////////////////////////////////////////////
 
-static SkImageDecoder* sk_libktx_dfactory(SkStreamRewindable* stream) {
-    if (SkKTXFile::is_ktx(stream)) {
-        return new SkKTXImageDecoder;
-    }
-    return nullptr;
-}
-
-static SkImageDecoder::Format get_format_ktx(SkStreamRewindable* stream) {
-    if (SkKTXFile::is_ktx(stream)) {
-        return SkImageDecoder::kKTX_Format;
-    }
-    return SkImageDecoder::kUnknown_Format;
-}
-
 SkImageEncoder* sk_libktx_efactory(SkImageEncoder::Type t) {
     return (SkImageEncoder::kKTX_Type == t) ? new SkKTXImageEncoder : nullptr;
 }
 
-static SkImageDecoder_DecodeReg gReg(sk_libktx_dfactory);
-static SkImageDecoder_FormatReg gFormatReg(get_format_ktx);
 static SkImageEncoder_EncodeReg gEReg(sk_libktx_efactory);