Fix product build

runtime/vm/dev_fs.cc

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "vm/dev_fs.h"
 
 #include "vm/hash_table.h"
 #include "vm/json_stream.h"
 #include "vm/lockers.h"
 #include "vm/object.h"
 #include "vm/unicode.h"
 
 namespace dart {
 
+#ifndef PRODUCT
+
 static const uint8_t decode_table[256] = {
   64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
   64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
   64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 62, 64, 64, 64, 63,
   52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 64, 64, 64, 64, 64, 64,
   64,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
   15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 64, 64, 64, 64, 64,
   64, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
   41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 64, 64, 64, 64, 64,
   64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
@@ skipping 332 matching lines @@
     return;
   }
 
   JSONObject jsobj(js);
   jsobj.AddProperty("type", "FSFile");
   jsobj.AddPropertyBase64("fileContents",
                           &((*file_contents)[0]),
                           file_contents->size());
 }
 
+#endif  // !PRODUCT
+
 }  // namespace dart