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

chrome/chrome.gyp

 # 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.
 {
   'variables': {
     'chromium_code': 1,
 
     'variables': {
       'version_py_path': 'tools/build/version.py',
       'version_path': 'VERSION',
@@ skipping 925 matching lines @@
         {
           'target_name': 'helper_app',
           'type': 'executable',
           'product_name': '<(mac_product_name) Helper',
           'mac_bundle': 1,
           'dependencies': [
             'chrome_dll',
             'infoplist_strings_tool',
           ],
           'sources': [
-            # chrome_exe_main_mac.mm's main() is the entry point for
+            # chrome_exe_main_mac.cc's main() is the entry point for
             # the "chrome" (browser app) target.  All it does is jump
             # to chrome_dll's ChromeMain.  This is appropriate for
             # helper processes too, because the logic to discriminate
             # between process types at run time is actually directed
             # by the --type command line argument processed by
-            # ChromeMain.  Sharing chrome_exe_main_mac.mm with the
+            # ChromeMain.  Sharing chrome_exe_main_mac.cc with the
             # browser app will suffice for now.
-            'app/chrome_exe_main_mac.mm',
+            'app/chrome_exe_main_mac.cc',
             'app/helper-Info.plist',
           ],
           # TODO(mark): Come up with a fancier way to do this.  It should only
           # be necessary to list helper-Info.plist once, not the three times it
           # is listed here.
           'mac_bundle_resources!': [
             'app/helper-Info.plist',
           ],
           # TODO(mark): For now, don't put any resources into this app.  Its
           # resources directory will be a symbolic link to the browser app's
@@ skipping 45 matching lines @@
               # Breakpad, Keystone, and Subersion keys are never placed into
               # the helper.
               'postbuild_name': 'Tweak Info.plist',
               'action': ['<(tweak_info_plist_path)',
                          '-b0',
                          '-k0',
                          '-s0',
                          '<(branding)',
                          '<(mac_bundle_id)'],
             },
+            {
+              # Make sure there isn't any Objective-C in the helper app's
+              # executable.
+              'postbuild_name': 'Verify No Objective-C',
+              'action': [
+                'tools/build/mac/verify_no_objc.sh',
+              ],
+            },
           ],
           'conditions': [
             ['mac_breakpad==1', {
               'variables': {
                 # A real .dSYM is needed for dump_syms to operate on.
                 'mac_real_dsym': 1,
               },
               'xcode_settings': {
                 # With mac_real_dsym set, strip_from_xcode won't be used.
                 # Specify CHROMIUM_STRIP_SAVE_FILE directly to Xcode.
@@ skipping 684 matching lines @@
             'destination': '<(PRODUCT_DIR)',
             'files': [
               '<(INTERMEDIATE_DIR)/repack/chrome.pak'
             ],
           },
         ],
       }],  # targets
     }],  # OS != "mac"
   ],  # 'conditions'
 }