Add early returns in CJBig2_TRDProc::decode_Arith when decode fails.

core/fxcodec/jbig2/JBig2_TrdProc.cpp

 // Copyright 2015 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "core/fxcodec/jbig2/JBig2_TrdProc.h"
 
 #include <memory>
 
@@ skipping 248 matching lines @@
     pIARI = IARI.get();
     pIARDW = IARDW.get();
     pIARDH = IARDH.get();
     pIARDX = IARDX.get();
     pIARDY = IARDY.get();
     pIAID = IAID.get();
   }
   std::unique_ptr<CJBig2_Image> SBREG(new CJBig2_Image(SBW, SBH));
   SBREG->fill(SBDEFPIXEL);
   int32_t STRIPT;
-  pIADT->decode(pArithDecoder, &STRIPT);
+  if (!pIADT->decode(pArithDecoder, &STRIPT))
+    return nullptr;
   STRIPT *= SBSTRIPS;
   STRIPT = -STRIPT;
   int32_t FIRSTS = 0;
   uint32_t NINSTANCES = 0;
   while (NINSTANCES < SBNUMINSTANCES) {
     int32_t CURS = 0;
     int32_t DT;
-    pIADT->decode(pArithDecoder, &DT);
+    if (!pIADT->decode(pArithDecoder, &DT))
+      return nullptr;
     DT *= SBSTRIPS;
     STRIPT += DT;
     bool bFirst = true;
     for (;;) {
       if (bFirst) {
         int32_t DFS;
         pIAFS->decode(pArithDecoder, &DFS);
         FIRSTS += DFS;
         CURS = FIRSTS;
         bFirst = false;
@@ skipping 108 matching lines @@
         CURS += WI - 1;
       } else if (TRANSPOSED == 1 && ((REFCORNER == JBIG2_CORNER_TOPLEFT) ||
                                      (REFCORNER == JBIG2_CORNER_TOPRIGHT))) {
         CURS += HI - 1;
       }
       ++NINSTANCES;
     }
   }
   return SBREG.release();
 }