Added unpacking step

chrome/installer/mac/app/MainDelegate.m

 // Copyright 2016 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.
 
 #import "MainDelegate.h"
 
 @implementation MainDelegate
 
 - (void)runApplication {
   OmahaCommunication* messenger = [[OmahaCommunication alloc] init];
   messenger.delegate = self;
 
   [messenger sendRequest];
 }
 
 - (void)onOmahaSuccessWithResponseBody:(NSData*)responseBody
                               AndError:(NSError*)error {
   if (error) {
     NSLog(@"error: %@", [error localizedDescription]);
     exit(1);
   }
   Downloader* download = [[Downloader alloc] init];
   download.delegate = self;
 
   [download downloadChromeImageToDownloadsDirectory:responseBody];
 }
 
 - (void)onDownloadSuccess {
-  // TODO: replace the line of code below with real code someday to unpack dmg
+  Unpacker* unpack = [[Unpacker alloc] init];
+  unpack.delegate = self;
+
+  [unpack unpackDMG];
+}
+
+- (void)onUnpackSuccess {
+  // TODO: replace with real code somehow
+  NSLog(@"finished unpacking");
   exit(0);
 }
 
-- (void)onUnpackSuccess {
-}
-
 @end