Zero jpeg_decompress_struct before calling jpeg_calc_output_dimensions().

src/codec/SkJpegCodec.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCodec.h"
 #include "SkJpegCodec.h"
 #include "SkJpegDecoderMgr.h"
@@ skipping 170 matching lines @@
     } else if (desiredScale > 0.375f) {
         scale = 2;
     } else if (desiredScale > 0.1875f) {
         scale = 4;
     } else {
         scale = 8;
     }
 
     // Set up a fake decompress struct in order to use libjpeg to calculate output dimensions
     jpeg_decompress_struct dinfo;
+    sk_bzero(&dinfo, sizeof(dinfo));
     dinfo.image_width = this->getInfo().width();
     dinfo.image_height = this->getInfo().height();
     dinfo.global_state = DSTATE_READY;
     dinfo.num_components = 0;
     dinfo.scale_num = 1;
     dinfo.scale_denom = scale;
     jpeg_calc_output_dimensions(&dinfo);
 
     // Return the calculated output dimensions for the given scale
     return SkISize::Make(dinfo.output_width, dinfo.output_height);
@@ skipping 137 matching lines @@
 
             // Finish the decode and indicate that the input was incomplete.
             jpeg_finish_decompress(dinfo);
             return fDecoderMgr->returnFailure("Incomplete image data", kIncompleteInput);
         }
     }
     jpeg_finish_decompress(dinfo);
 
     return kSuccess;
 }