This CL adds support for extension in GYP.

pylib/gyp/xcodeproj_file.py

 # Copyright (c) 2012 Google Inc. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Xcode project file generator.
 
 This module is both an Xcode project file generator and a documentation of the
 Xcode project file format.  Knowledge of the project file format was gained
 based on extensive experience with Xcode, and by making changes to projects in
 Xcode.app and observing the resultant changes in the associated project files.
@@ skipping 2219 matching lines @@
     'buildPhases':      [1, XCBuildPhase,     1, 1,
                          [PBXSourcesBuildPhase(), PBXFrameworksBuildPhase()]],
     'buildRules':       [1, PBXBuildRule,     1, 1, []],
     'productReference': [0, PBXFileReference, 0, 1],
     'productType':      [0, str,              0, 1],
   })
 
   # Mapping from Xcode product-types to settings.  The settings are:
   #  filetype : used for explicitFileType in the project file
   #  prefix : the prefix for the file name
-  #  suffix : the suffix for the filen ame
+  #  suffix : the suffix for the file name
   _product_filetypes = {
     'com.apple.product-type.application':       ['wrapper.application',
                                                  '', '.app'],
+    'com.apple.product-type.app-extension':     ['wrapper.app-extension',
+                                                 '', '.appex'],
     'com.apple.product-type.bundle':            ['wrapper.cfbundle',
                                                  '', '.bundle'],
     'com.apple.product-type.framework':         ['wrapper.framework',
                                                  '', '.framework'],
     'com.apple.product-type.library.dynamic':   ['compiled.mach-o.dylib',
                                                  'lib', '.dylib'],
     'com.apple.product-type.library.static':    ['archive.ar',
                                                  'lib', '.a'],
     'com.apple.product-type.tool':              ['compiled.mach-o.executable',
                                                  '', ''],
@@ skipping 626 matching lines @@
       self._XCPrint(file, 0, '/* Begin ' + class_name + ' section */\n')
       for object in sorted(objects_by_class[class_name],
                            cmp=lambda x, y: cmp(x.id, y.id)):
         object.Print(file)
       self._XCPrint(file, 0, '/* End ' + class_name + ' section */\n')
 
     if self._should_print_single_line:
       self._XCPrint(file, 0, '}; ')
     else:
       self._XCPrint(file, 1, '};\n')