Fix silent truncations when extracting values from CheckedNumeric

chrome/utility/safe_browsing/mac/udif.cc

 // Copyright 2015 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.
 
 #include "chrome/utility/safe_browsing/mac/udif.h"
 
 #include <CoreFoundation/CoreFoundation.h>
 #include <bzlib.h>
 #include <libkern/OSByteOrder.h>
 #include <uuid/uuid.h>
@@ skipping 663 matching lines @@
   if (!decompress_read_offset.IsValid()) {
     DLOG(ERROR) << "Partition decompress read offset overflows";
     return -1;
   }
 
   if (!chunk_stream_ || chunk != chunk_stream_->chunk()) {
     chunk_stream_.reset(
         new UDIFBlockChunkReadStream(stream_, block_size_, chunk));
   }
   current_chunk_ = chunk_number;
-  if (chunk_stream_->Seek(decompress_read_offset.ValueOrDie(), SEEK_SET) == -1)
+  if (chunk_stream_->Seek(
+          base::ValueOrDieForType<off_t>(decompress_read_offset), SEEK_SET) ==
+      -1)
     return -1;
 
   return offset;
 }
 
 UDIFBlockChunkReadStream::UDIFBlockChunkReadStream(ReadStream* stream,
                                                    uint16_t block_size,
                                                    const UDIFBlockChunk* chunk)
     : stream_(stream),
       chunk_(chunk),
@@ skipping 168 matching lines @@
                 << chunk_->compressed_offset;
     return false;
   }
   return true;
 }
 
 }  // namespace
 
 }  // namespace dmg
 }  // namespace safe_browsing