Add optimize_coding setting for JPEG encoding.

src/images/SkImageDecoder_libjpeg.cpp

 /*
  * Copyright 2007 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "SkImageDecoder.h"
 #include "SkImageEncoder.h"
@@ skipping 940 matching lines @@
         cinfo.image_height = bm.height();
         cinfo.input_components = 3;
 #ifdef WE_CONVERT_TO_YUV
         cinfo.in_color_space = JCS_YCbCr;
 #else
         cinfo.in_color_space = JCS_RGB;
 #endif
         cinfo.input_gamma = 1;
 
         jpeg_set_defaults(&cinfo);
+        cinfo.optimize_coding = TRUE;
         jpeg_set_quality(&cinfo, quality, TRUE /* limit to baseline-JPEG values */);
 #ifdef DCT_IFAST_SUPPORTED
         cinfo.dct_method = JDCT_IFAST;
 #endif
 
         jpeg_start_compress(&cinfo, TRUE);
 
         const int       width = bm.width();
         uint8_t*        oneRowP = oneRow.reset(width * 3);
 
@@ skipping 52 matching lines @@
     return SkImageDecoder::kUnknown_Format;
 }
 
 static SkImageEncoder* sk_libjpeg_efactory(SkImageEncoder::Type t) {
     return (SkImageEncoder::kJPEG_Type == t) ? new SkJPEGImageEncoder : nullptr;
 }
 
 static SkImageDecoder_DecodeReg gDReg(sk_libjpeg_dfactory);
 static SkImageDecoder_FormatReg gFormatReg(get_format_jpeg);
 static SkImageEncoder_EncodeReg gEReg(sk_libjpeg_efactory);