Have PNaCl use debug pexe URL instead of stripped pexe w/ kEnableNaClDebug

ppapi/native_client/src/trusted/plugin/pnacl_options.cc

 // Copyright (c) 2013 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 "ppapi/native_client/src/trusted/plugin/pnacl_options.h"
 
 #include <iterator>
 #include <vector>
 
 #include "native_client/src/include/nacl_string.h"
 
 namespace plugin {
 
-PnaclOptions::PnaclOptions() : translate_(false), opt_level_(2) { }
+PnaclOptions::PnaclOptions()
+    : translate_(false),
+      is_debug_(false),
+      opt_level_(2) {
+}
 
 PnaclOptions::~PnaclOptions() {
 }
 
 void PnaclOptions::set_opt_level(int32_t l) {
   if (l <= 0) {
     opt_level_ = 0;
     return;
   }
   // Currently only allow 0 or 2, since that is what we test.
   opt_level_ = 2;
 }
 
 std::vector<char> PnaclOptions::GetOptCommandline() const {
   std::vector<char> result;
   nacl::string str;
 
   nacl::stringstream ss;
   ss << "-O" << opt_level_;
+  // Debug info is only available in LLVM format pexes,
+  // not in PNaCl format pexes.
+  if (is_debug_)
+    ss << "\x00-bitcode-format=llvm";
   str = ss.str();
 
   std::copy(str.begin(), str.end(), std::back_inserter(result));
   result.push_back('\x00');
 
   return result;
 }
 
 }  // namespace plugin