Don't strip main from the browser or helper app executables

chrome/app/chrome_exe_main.mm

 // Copyright (c) 2010 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).
 
 #include <stdlib.h>
 
 extern "C" {
 int ChromeMain(int argc, char** argv);
 }
 
+__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);
 }