Migrate mac installer to delegate-driven model

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 <Foundation/Foundation.h>
+#import <Cocoa/Cocoa.h>

[Mark Mentovai, 2016/07/19 21:07:40]

Sort ’em! But if you’re #importing Cocoa, there’s no need to also #import
Foundation.

+
+#import "Downloader.h"
+#import "MainDelegate.h"
+#import "OmahaCommunication.h"
+#import "OmahaXMLRequest.h"
+#import "SystemInfo.h"
+
+@implementation MainDelegate
+
+- (void)talkToOmaha {
+  NSXMLDocument* requestBody = [OmahaXMLRequest createXMLRequestBody];
+
+  OmahaCommunication* messenger =
+      [[OmahaCommunication alloc] initWithBody:requestBody];
+  [messenger setDelegate:self];

[Sidney San Martín, 2016/07/19 23:19:20]

Pretty trivial: you can just say `messenger.delegate = self;`, instead.

+
+  [messenger sendRequest];
+}
+
+- (void)downloadChromeWithData:(NSData*)data {
+  Downloader* download = [[Downloader alloc] init];
+  [download setDelegate:self];

[Sidney San Martín, 2016/07/19 23:19:20]

Ditto, could be `download.delegate = self;`.

+
+  [download downloadChromeImageToDownloadsDirectory:data];
+}
+
+- (void)unpackDMG {
+  // TODO: replace the line of code below with real code someday
+  exit(0);
+}
+
+@end