Revert of Delete FORMAT_RGB and legacy libjpeg support from gfx::JpegCodec

ui/gfx/codec/jpeg_codec.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_GFX_CODEC_JPEG_CODEC_H_
 #define UI_GFX_CODEC_JPEG_CODEC_H_
 
 #include <stddef.h>
 
 #include <memory>
 #include <vector>
 
 #include "ui/gfx/codec/codec_export.h"
 
 class SkBitmap;
 
 namespace gfx {
 
 // Interface for encoding/decoding JPEG data. This is a wrapper around libjpeg,
 // which has an inconvenient interface for callers. This is only used for UI
 // elements, WebKit has its own more complicated JPEG decoder which handles,
 // among other things, partially downloaded data.
 class CODEC_EXPORT JPEGCodec {
  public:
   enum ColorFormat {
+    // 3 bytes per pixel (packed), in RGB order regardless of endianness.
+    // This is the native JPEG format.
+    FORMAT_RGB,
+
     // 4 bytes per pixel, in RGBA order in mem regardless of endianness.
     FORMAT_RGBA,
 
     // 4 bytes per pixel, in BGRA order in mem regardless of endianness.
     // This is the default Windows DIB order.
     FORMAT_BGRA,
 
     // 4 bytes per pixel, it can be either RGBA or BGRA. It depends on the bit
     // order in kARGB_8888_Config skia bitmap.
     FORMAT_SkBitmap
   };
 
+  enum LibraryVariant {
+    SYSTEM_LIBJPEG = 0,
+    LIBJPEG_TURBO,
+    IJG_LIBJPEG,
+  };
+
+  // This method helps identify at run time which library chromium is using.
+  static LibraryVariant JpegLibraryVariant();
+
   // Encodes the given raw 'input' data, with each pixel being represented as
   // given in 'format'. The encoded JPEG data will be written into the supplied
   // vector and true will be returned on success. On failure (false), the
   // contents of the output buffer are undefined.
   //
   // w, h: dimensions of the image
   // row_byte_width: the width in bytes of each row. This may be greater than
   //   w * bytes_per_pixel if there is extra padding at the end of each row
   //   (often, each row is padded to the next machine word).
   // quality: an integer in the range 0-100, where 100 is the highest quality.
@@ skipping 11 matching lines @@
 
   // Decodes the JPEG data contained in input of length input_size. If
   // successful, a SkBitmap is created and returned.
   static std::unique_ptr<SkBitmap> Decode(const unsigned char* input,
                                           size_t input_size);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_CODEC_JPEG_CODEC_H_