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

chrome/chrome_exe.gypi

 # 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.
 
 {
   'target_defaults': {
     'variables': {
       'chrome_exe_target': 0,
     },
     'target_conditions': [
       ['chrome_exe_target==1', {
         'sources': [
           # .cc, .h, and .mm files under app that are used on all
           # platforms, including both 32-bit and 64-bit Windows.
           # Test files are not included.
           'app/breakpad_win.cc',
           'app/breakpad_win.h',
           'app/chrome_exe_main_gtk.cc',
-          'app/chrome_exe_main_mac.mm',
+          'app/chrome_exe_main_mac.cc',
           'app/chrome_exe_main_win.cc',
           'app/chrome_exe_resource.h',
           'app/client_util.cc',
           'app/client_util.h',
           'app/hard_error_handler_win.cc',
           'app/hard_error_handler_win.h',
           'app/scoped_ole_initializer.h',
           # TODO(bradnelson): once automatic generation of 64 bit targets on
           # Windows is ready, take this out and add a dependency on
           # content_common.gypi.
@@ skipping 363 matching lines @@
               # "More Helpers" share a UUID with the original helper, there's
               # no need to run dsymutil or dump_syms again. All helpers can
               # share the same .dSYM and Breakpad symbol file.
               'postbuild_name': 'Make More Helpers',
               'action': [
                 'tools/build/mac/make_more_helpers.sh',
                 '<(version_full)',
                 '<(mac_product_name)',
               ],
             },
+            {
+              # Make sure there isn't any Objective-C in the browser app's
+              # executable.
+              'postbuild_name': 'Verify No Objective-C',
+              'action': [
+                'tools/build/mac/verify_no_objc.sh',
+              ],
+            },
           ],  # postbuilds
         }],
         ['OS=="linux"', {
           'conditions': [
             ['branding=="Chrome"', {
               'dependencies': [
                 'linux_installer_configs',
               ],
             }],
             ['selinux==0', {
@@ skipping 118 matching lines @@
           'configurations': {
             'Common_Base': {
               'msvs_target_platform': 'x64',
             },
           },
         },
       ],
     }],
   ],
 }