Reland https://codereview.chromium.org/581983003/: Enable ASan default options on Mac.

chrome/app/chrome_exe_main_mac.cc

 // Copyright (c) 2011 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.
 
 // The entry point for all Mac Chromium processes, including the outer app
 // bundle (browser) and helper app (renderer, plugin, and friends).
 
-#if defined(ADDRESS_SANITIZER)
-#include <crt_externs.h>  // for _NSGetArgc, _NSGetArgv
-#include <string.h>
-#endif  // ADDRESS_SANITIZER
 #include <stdlib.h>
 
-#if defined(ADDRESS_SANITIZER)
-// NaCl requires its own SEGV handler, so we need to add handle_segv=0 to
-// ASAN_OPTIONS. This is done by injecting __asan_default_options into the
-// executable.
-// Because there's no distinct NaCl executable on OSX, we have to look at the
-// command line arguments to understand whether the process is a NaCl loader.
-
-static const char kNaClDefaultOptions[] = "handle_segv=0";
-static const char kNaClFlag[] = "--type=nacl-loader";
-
-extern "C"
-// __asan_default_options() is called at ASan initialization, so it must
-// not be instrumented with ASan -- thus the "no_sanitize_address" attribute.
-__attribute__((no_sanitize_address))
-// The function isn't referenced from the executable itself. Make sure it isn't
-// stripped by the linker.
-__attribute__((used))
-__attribute__((visibility("default")))
-const char* __asan_default_options()  {
-  char*** argvp = _NSGetArgv();
-  int* argcp = _NSGetArgc();
-  if (!argvp || !argcp) return NULL;
-  char** argv = *argvp;
-  int argc = *argcp;
-  for (int i = 0; i < argc; ++i) {
-    if (strcmp(argv[i], kNaClFlag) == 0) {
-      return kNaClDefaultOptions;
-    }
-  }
-  return NULL;
-}
-#endif  // ADDRESS_SANITIZER
-
 extern "C" {
 int ChromeMain(int argc, char** argv);
 }  // extern "C"
 
 __attribute__((visibility("default")))
 int main(int argc, char* argv[]) {
   int rv = ChromeMain(argc, argv);
 
   // exit, don't return from main, to avoid the apparent removal of main from
   // stack backtraces under tail call optimization.
   exit(rv);
 }