Migrate mac installer to delegate-driven model

chrome/installer/mac/app/main.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 "Downloader.h"
 #import "OmahaCommunication.h"
 #import "OmahaXMLRequest.h"
 #import "SystemInfo.h"
 
-// TODO: add a class that takes care of what main is doing now
-void talkToOmahaThenExecuteBlock(OmahaRequestCompletionHandler block) {
+void talkToOmaha() {
   NSXMLDocument* requestBody = [OmahaXMLRequest createXMLRequestBody];
   OmahaCommunication* messenger =
       [[OmahaCommunication alloc] initWithBody:requestBody];
-  [messenger sendRequestWithBlock:block];
-}
-
-int main() {
-  talkToOmahaThenExecuteBlock(^(NSData* data, NSError* error) {
+  [messenger sendRequestWithBlock:^(NSData* data, NSError* error) {
     if (error) {
       NSLog(@"%@", [error localizedDescription]);
       return;
     }
-    Downloader* download = [[Downloader alloc] init];
-    [download downloadChromeImageToDownloadsDirectory:data];
-  });
+
+    downloadChrome();

[Sidney San Martín, 2016/07/18 18:28:52]

It's confusing that talkToOmaha() also starts the download. A middle ground
would be to still have it take a block (the function can still be called
talkToOmaha), and then in main():

    talkToOmaha(^{ downloadChrome(); });

Or, talkToOmaha needs a better name.

+  }];
+}
+
+void downloadChrome() {
+  Downloader* download = [[Downloader alloc] init];
+  [download downloadChromeImageToDownloadsDirectory:data];
+}
+
+int main() {
+  talkToOmaha();
 
   // [[NSRunLoop mainRunLoop] run];
   [[NSRunLoop mainRunLoop]
       runUntilDate:[NSDate dateWithTimeIntervalSinceNow:3]];

[Sidney San Martín, 2016/07/18 18:28:52]

You should probably just call `run`, and then exit() when you want the app to
terminate. (When you have a GUI, `[NSApp terminate:nil]` will also do the job).

   return 1;
 }