Delete FORMAT_RGB and legacy libjpeg support from gfx::JpegCodec

ui/gfx/codec/jpeg_codec.cc

Index: ui/gfx/codec/jpeg_codec.cc
diff --git a/ui/gfx/codec/jpeg_codec.cc b/ui/gfx/codec/jpeg_codec.cc
index 6d926378bec130b53d70bbb510a1287f42b78a08..3dc5ad6235668d4323f8f0d8268561d6ea8674bc 100644
--- a/ui/gfx/codec/jpeg_codec.cc
+++ b/ui/gfx/codec/jpeg_codec.cc
@@ -43,17 +43,6 @@ void ErrorExit(jpeg_common_struct* cinfo) {
 
 }  // namespace
 
-// This method helps identify at run time which library chromium is using.
-JPEGCodec::LibraryVariant JPEGCodec::JpegLibraryVariant() {
-#if defined(USE_SYSTEM_LIBJPEG)
-  return SYSTEM_LIBJPEG;
-#elif defined(USE_LIBJPEG_TURBO)
-  return LIBJPEG_TURBO;
-#else
-  return IJG_LIBJPEG;
-#endif
-}
-
 // Encoder ---------------------------------------------------------------------
 //
 // This code is based on nsJPEGEncoder from Mozilla.
@@ -144,33 +133,6 @@ void TermDestination(jpeg_compress_struct* cinfo) {
   state->out->resize(state->image_buffer_used);
 }
 
-#if !defined(JCS_EXTENSIONS)
-// Converts RGBA to RGB (removing the alpha values) to prepare to send data to
-// libjpeg. This converts one row of data in rgba with the given width in
-// pixels the the given rgb destination buffer (which should have enough space
-// reserved for the final data).
-void StripAlpha(const unsigned char* rgba, int pixel_width, unsigned char* rgb)
-{
-  for (int x = 0; x < pixel_width; x++)
-    memcpy(&rgb[x * 3], &rgba[x * 4], 3);
-}
-
-// Converts BGRA to RGB by reordering the color components and dropping the
-// alpha. This converts  one row of data in rgba with the given width in
-// pixels the the given rgb destination buffer (which should have enough space
-// reserved for the final data).
-void BGRAtoRGB(const unsigned char* bgra, int pixel_width, unsigned char* rgb)
-{
-  for (int x = 0; x < pixel_width; x++) {
-    const unsigned char* pixel_in = &bgra[x * 4];
-    unsigned char* pixel_out = &rgb[x * 3];
-    pixel_out[0] = pixel_in[2];
-    pixel_out[1] = pixel_in[1];
-    pixel_out[2] = pixel_in[0];
-  }
-}
-#endif  // !defined(JCS_EXTENSIONS)
-
 // This class destroys the given jpeg_compress object when it goes out of
 // scope. It simplifies the error handling in Encode (and even applies to the
 // success case).
@@ -204,9 +166,6 @@ bool JPEGCodec::Encode(const unsigned char* input, ColorFormat format,
   CompressDestroyer destroyer;
   destroyer.SetManagedObject(&cinfo);
   output->clear();
-#if !defined(JCS_EXTENSIONS)
-  unsigned char* row_buffer = NULL;
-#endif
 
   // We set up the normal JPEG error routines, then override error_exit.
   // This must be done before the call to create_compress.
@@ -222,9 +181,6 @@ bool JPEGCodec::Encode(const unsigned char* input, ColorFormat format,
     // goto using a call to longjmp."  So we delete the CompressDestroyer's
     // object manually instead.
     destroyer.DestroyManagedObject();
-#if !defined(JCS_EXTENSIONS)
-    delete[] row_buffer;
-#endif
     return false;
   }
 
@@ -233,22 +189,16 @@ bool JPEGCodec::Encode(const unsigned char* input, ColorFormat format,
 
   cinfo.image_width = w;
   cinfo.image_height = h;
-  cinfo.input_components = 3;
-#ifdef JCS_EXTENSIONS
+  cinfo.input_components = 4;
   // Choose an input colorspace and return if it is an unsupported one. Since
   // libjpeg-turbo supports all input formats used by Chromium (i.e. RGB, RGBA,
   // and BGRA), we just map the input parameters to a colorspace used by
   // libjpeg-turbo.
-  if (format == FORMAT_RGB) {
-    cinfo.input_components = 3;
-    cinfo.in_color_space = JCS_RGB;
-  } else if (format == FORMAT_RGBA ||
-             (format == FORMAT_SkBitmap && SK_R32_SHIFT == 0)) {
-    cinfo.input_components = 4;
+  if (format == FORMAT_RGBA ||
+      (format == FORMAT_SkBitmap && SK_R32_SHIFT == 0)) {
     cinfo.in_color_space = JCS_EXT_RGBX;
   } else if (format == FORMAT_BGRA ||
              (format == FORMAT_SkBitmap && SK_B32_SHIFT == 0)) {
-    cinfo.input_components = 4;
     cinfo.in_color_space = JCS_EXT_BGRX;
   } else {
     // We can exit this function without calling jpeg_destroy_compress() because
@@ -256,9 +206,6 @@ bool JPEGCodec::Encode(const unsigned char* input, ColorFormat format,
     NOTREACHED() << "Invalid pixel format";
     return false;
   }
-#else
-  cinfo.in_color_space = JCS_RGB;
-#endif
   cinfo.data_precision = 8;
 
   jpeg_set_defaults(&cinfo);
@@ -277,7 +224,6 @@ bool JPEGCodec::Encode(const unsigned char* input, ColorFormat format,
   jpeg_start_compress(&cinfo, 1);
 
   // feed it the rows, doing necessary conversions for the color format
-#ifdef JCS_EXTENSIONS
   // This function already returns when the input format is not supported by
   // libjpeg-turbo and needs conversion. Therefore, we just encode lines without
   // conversions.
@@ -285,37 +231,6 @@ bool JPEGCodec::Encode(const unsigned char* input, ColorFormat format,
     const unsigned char* row = &input[cinfo.next_scanline * row_byte_width];
     jpeg_write_scanlines(&cinfo, const_cast<unsigned char**>(&row), 1);
   }
-#else
-  if (format == FORMAT_RGB) {
-    // no conversion necessary
-    while (cinfo.next_scanline < cinfo.image_height) {
-      const unsigned char* row = &input[cinfo.next_scanline * row_byte_width];
-      jpeg_write_scanlines(&cinfo, const_cast<unsigned char**>(&row), 1);
-    }
-  } else {
-    // get the correct format converter
-    void (*converter)(const unsigned char* in, int w, unsigned char* rgb);
-    if (format == FORMAT_RGBA ||
-        (format == FORMAT_SkBitmap && SK_R32_SHIFT == 0)) {
-      converter = StripAlpha;
-    } else if (format == FORMAT_BGRA ||
-               (format == FORMAT_SkBitmap && SK_B32_SHIFT == 0)) {
-      converter = BGRAtoRGB;
-    } else {
-      NOTREACHED() << "Invalid pixel format";
-      return false;
-    }
-
-    // output row after converting
-    row_buffer = new unsigned char[w * 3];
-
-    while (cinfo.next_scanline < cinfo.image_height) {
-      converter(&input[cinfo.next_scanline * row_byte_width], w, row_buffer);
-      jpeg_write_scanlines(&cinfo, &row_buffer, 1);
-    }
-    delete[] row_buffer;
-  }
-#endif
 
   jpeg_finish_compress(&cinfo);
   return true;
@@ -398,31 +313,6 @@ void SkipInputData(j_decompress_ptr cinfo, long num_bytes) {
 void TermSource(j_decompress_ptr cinfo) {
 }
 
-#if !defined(JCS_EXTENSIONS)
-// Converts one row of rgb data to rgba data by adding a fully-opaque alpha
-// value.
-void AddAlpha(const unsigned char* rgb, int pixel_width, unsigned char* rgba) {
-  for (int x = 0; x < pixel_width; x++) {
-    memcpy(&rgba[x * 4], &rgb[x * 3], 3);
-    rgba[x * 4 + 3] = 0xff;
-  }
-}
-
-// Converts one row of RGB data to BGRA by reordering the color components and
-// adding alpha values of 0xff.
-void RGBtoBGRA(const unsigned char* bgra, int pixel_width, unsigned char* rgb)
-{
-  for (int x = 0; x < pixel_width; x++) {
-    const unsigned char* pixel_in = &bgra[x * 3];
-    unsigned char* pixel_out = &rgb[x * 4];
-    pixel_out[0] = pixel_in[2];
-    pixel_out[1] = pixel_in[1];
-    pixel_out[2] = pixel_in[0];
-    pixel_out[3] = 0xff;
-  }
-}
-#endif  // !defined(JCS_EXTENSIONS)
-
 // This class destroys the given jpeg_decompress object when it goes out of
 // scope. It simplifies the error handling in Decode (and even applies to the
 // success case).
@@ -496,16 +386,12 @@ bool JPEGCodec::Decode(const unsigned char* input, size_t input_size,
     case JCS_GRAYSCALE:
     case JCS_RGB:
     case JCS_YCbCr:
-#ifdef JCS_EXTENSIONS
       // Choose an output colorspace and return if it is an unsupported one.
       // Same as JPEGCodec::Encode(), libjpeg-turbo supports all input formats
       // used by Chromium (i.e. RGB, RGBA, and BGRA) and we just map the input
       // parameters to a colorspace.
-      if (format == FORMAT_RGB) {
-        cinfo.out_color_space = JCS_RGB;
-        cinfo.output_components = 3;
-      } else if (format == FORMAT_RGBA ||
-                 (format == FORMAT_SkBitmap && SK_R32_SHIFT == 0)) {
+      if (format == FORMAT_RGBA ||
+          (format == FORMAT_SkBitmap && SK_R32_SHIFT == 0)) {
         cinfo.out_color_space = JCS_EXT_RGBX;
         cinfo.output_components = 4;
       } else if (format == FORMAT_BGRA ||
@@ -518,9 +404,6 @@ bool JPEGCodec::Decode(const unsigned char* input, size_t input_size,
         NOTREACHED() << "Invalid pixel format";
         return false;
       }
-#else
-      cinfo.out_color_space = JCS_RGB;
-#endif
       break;
     case JCS_CMYK:
     case JCS_YCCK:
@@ -530,9 +413,6 @@ bool JPEGCodec::Decode(const unsigned char* input, size_t input_size,
       // care about these anyway.
       return false;
   }
-#ifndef JCS_EXTENSIONS
-  cinfo.output_components = 3;
-#endif
 
   jpeg_calc_output_dimensions(&cinfo);
   *w = cinfo.output_width;
@@ -544,7 +424,6 @@ bool JPEGCodec::Decode(const unsigned char* input, size_t input_size,
   // how to align row lengths as we do for the compressor.
   int row_read_stride = cinfo.output_width * cinfo.output_components;
 
-#ifdef JCS_EXTENSIONS
   // Create memory for a decoded image and write decoded lines to the memory
   // without conversions same as JPEGCodec::Encode().
   int row_write_stride = row_read_stride;
@@ -555,49 +434,6 @@ bool JPEGCodec::Decode(const unsigned char* input, size_t input_size,
     if (!jpeg_read_scanlines(&cinfo, &rowptr, 1))
       return false;
   }
-#else
-  if (format == FORMAT_RGB) {
-    // easy case, row needs no conversion
-    int row_write_stride = row_read_stride;
-    output->resize(row_write_stride * cinfo.output_height);
-
-    for (int row = 0; row < static_cast<int>(cinfo.output_height); row++) {
-      unsigned char* rowptr = &(*output)[row * row_write_stride];
-      if (!jpeg_read_scanlines(&cinfo, &rowptr, 1))
-        return false;
-    }
-  } else {
-    // Rows need conversion to output format: read into a temporary buffer and
-    // expand to the final one. Performance: we could avoid the extra
-    // allocation by doing the expansion in-place.
-    int row_write_stride;
-    void (*converter)(const unsigned char* rgb, int w, unsigned char* out);
-    if (format == FORMAT_RGBA ||
-        (format == FORMAT_SkBitmap && SK_R32_SHIFT == 0)) {
-      row_write_stride = cinfo.output_width * 4;
-      converter = AddAlpha;
-    } else if (format == FORMAT_BGRA ||
-               (format == FORMAT_SkBitmap && SK_B32_SHIFT == 0)) {
-      row_write_stride = cinfo.output_width * 4;
-      converter = RGBtoBGRA;
-    } else {
-      NOTREACHED() << "Invalid pixel format";
-      jpeg_destroy_decompress(&cinfo);
-      return false;
-    }
-
-    output->resize(row_write_stride * cinfo.output_height);
-
-    std::unique_ptr<unsigned char[]> row_data(
-        new unsigned char[row_read_stride]);
-    unsigned char* rowptr = row_data.get();
-    for (int row = 0; row < static_cast<int>(cinfo.output_height); row++) {
-      if (!jpeg_read_scanlines(&cinfo, &rowptr, 1))
-        return false;
-      converter(rowptr, *w, &(*output)[row * row_write_stride]);
-    }
-  }
-#endif
 
   jpeg_finish_decompress(&cinfo);
   jpeg_destroy_decompress(&cinfo);