This CL adds support for extension in GYP.

test/ios/extension/ActionExtension/ActionViewController.m

+// Copyright (c) 2014 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.
+
+#import "ActionViewController.h"
+#import <MobileCoreServices/MobileCoreServices.h>
+
+@interface ActionViewController ()
+
+@end
+
+@implementation ActionViewController
+
+- (void)viewDidLoad {
+  [super viewDidLoad];
+}
+
+- (void)didReceiveMemoryWarning {
+  [super didReceiveMemoryWarning];
+  // Dispose of any resources that can be recreated.
+}
+
+- (IBAction)done {
+  // Return any edited content to the host app.
+  // This template doesn't do anything, so we just echo the passed in items.
+  [self.extensionContext
+      completeRequestReturningItems:self.extensionContext.inputItems
+      completionHandler:nil];
+}
+
+@end