Merge "Force compressing ALPHA_8 to fail"

bool Bitmap::compress(const SkBitmap& bitmap, JavaCompressFormat format,

                      int32_t quality, SkWStream* stream) {

    if (bitmap.colorType() == kAlpha_8_SkColorType) {

        // None of the JavaCompressFormats have a sensible way to compress an

        // ALPHA_8 Bitmap. SkPngEncoder will compress one, but it uses a non-

        // standard format that most decoders do not understand, so this is

        // likely not useful.

        return false;

    }

    SkEncodedImageFormat fm;

    switch (format) {

        case JavaCompressFormat::Jpeg: