Don't build the main executable binaries as Objective-C

chrome/app/chrome_exe_main_gtk.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.
 
 #include "base/process_util.h"
 #include "build/build_config.h"
 #include "chrome/browser/first_run/upgrade_util.h"
 
 // The entry point for all invocations of Chromium, browser and renderer. On
 // windows, this does nothing but load chrome.dll and invoke its entry point in
 // order to make it easy to update the app from GoogleUpdate. We don't need
 // that extra layer with on linux.
 //
-// TODO(tc): This is similar to chrome_exe_main_mac.mm.  After it's
+// TODO(tc): This is similar to chrome_exe_main_mac.cc.  After it's
 // more clear what needs to go here, we should evaluate whether or not
-// to merge this file with chrome_exe_main_mac.mm.
+// to merge this file with chrome_exe_main_mac.cc.
 
 extern "C" {
 int ChromeMain(int argc, const char** argv);
 
 #if defined(OS_POSIX) && !defined(OS_MACOSX) && defined(USE_TCMALLOC)
 int tc_set_new_mode(int mode);
 #endif
 }
 
 int main(int argc, const char** argv) {
@@ skipping 19 matching lines @@
   int return_code = ChromeMain(argc, argv);
 
 #if defined(OS_LINUX) && !defined(OS_CHROMEOS)
   // Launch a new instance if we're shutting down because we detected an
   // upgrade in the persistent mode.
   upgrade_util::RelaunchChromeBrowserWithNewCommandLineIfNeeded();
 #endif
 
   return return_code;
 }