flags and hacks to get MSAN bot going

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 491 matching lines @@
 
     //  Possibly skip initial rows [sampler.srcY0]
     if (!skip_src_rows(&cinfo, srcRow, sampler.srcY0())) {
         return return_failure(cinfo, *bm, "skip rows");
     }
 
     // now loop through scanlines until y == bm->height() - 1
     for (int y = 0;; y++) {
         JSAMPLE* rowptr = (JSAMPLE*)srcRow;
         int row_count = jpeg_read_scanlines(&cinfo, &rowptr, 1);
+        sk_msan_mark_initialized(srcRow, srcRow + cinfo.output_width * srcBytesPerPixel,
+                                 "skbug.com/4550");
         if (0 == row_count) {
             // if row_count == 0, then we didn't get a scanline,
             // so return early.  We will return a partial image.
             fill_below_level(y, bm);
             cinfo.output_scanline = cinfo.output_height;
             jpeg_finish_decompress(&cinfo);
             return kPartialSuccess;
         }
         if (this->shouldCancelDecode()) {
             return return_failure(cinfo, *bm, "shouldCancelDecode");
         }
 
         if (JCS_CMYK == cinfo.out_color_space) {
             convert_CMYK_to_RGB(srcRow, cinfo.output_width);
         }
 
-        sk_msan_mark_initialized(srcRow, srcRow + cinfo.output_width * srcBytesPerPixel,
-                                 "skbug.com/4550");
 
         sampler.next(srcRow);
         if (bm->height() - 1 == y) {
             // we're done
             break;
         }
 
         if (!skip_src_rows(&cinfo, srcRow, sampler.srcDY() - 1)) {
             return return_failure(cinfo, *bm, "skip rows");
         }
@@ skipping 488 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);