Initial commit for Chrome metainstaller on Mac.

chrome/installer/mac/app/NetworkCommunication.h

+// 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.
+
+#ifndef CHROME_INSTALLER_MAC_APP_NETWORKCOMMUNICATION_H_
+#define CHROME_INSTALLER_MAC_APP_NETWORKCOMMUNICATION_H_
+
+#import <Foundation/Foundation.h>
+
+typedef void (^DataTaskCompletionHandler)(NSData*, NSURLResponse*, NSError*);
+typedef void (^DownloadTaskCompletionHandler)(NSURL*, NSURLResponse*, NSError*);
+
+@interface NetworkCommunication : NSObject
+
+@property(nonatomic, copy) NSMutableURLRequest* request;
+// Question: Our current design of the project thus far involves having one
+//           NSURLSession run the whole show. Thoughts? Is this one of those
+//           things that don't really matter, or does it have a positive /

[Elly Fong-Jones, 2016/07/06 15:22:01]

I think it's fine to just have one NSURLSession, but you could make one per
purpose instead if you want to.

+//           negative impact on our project?
+@property(nonatomic, copy) NSURLSession* session;
+// The user of this class must set these handlers if functionality is needed at
+// the completion of a URLSession task.
+@property(nonatomic, copy) DataTaskCompletionHandler dataResponseHandler;
+@property(nonatomic, copy) DownloadTaskCompletionHandler downloadResponseHandler;
+
+- (id)init;
+- (id)initWithDelegate:(id) delegate;
+
+// Creates a mutable URLRequest object as an instance variable, then returns it
+// so the caller has a chance to edit it before sending the request out.
+// Contrary to the assumption in Objective-C that all return values are returned
+// by VALUE, it seems that changes made to the returned object outside of this
+// class are retained.
+- (NSMutableURLRequest*)createRequestWithURLasString:(NSString*) urlString
+                                          andXMLBody:(NSXMLDocument*) body;
+// Adds a data task to the run loop using the request instance variable.
+- (NSURLSessionDataTask*)sendDataRequest;

[Elly Fong-Jones, 2016/07/06 15:22:01]

Hm... sendDataRequestWithCompletionHandler:? Will anyone ever want to do
requests with no way to tell if they completed or failed?

Also, returning the underlying NSURLSessionDataTasks seems like a bit of an
abstraction violation to me - there's no reason the caller here should care that
NSURLSession is in use, right?

[Anna Zeng, 2016/07/07 15:24:53]

including the completion handler means that delegate functions relevant to that
data task would not trigger.

+// Adds a download task to the run loop using the request instance variable.
+- (NSURLSessionDownloadTask*)sendDownloadRequest;
+
+@end
+
+#endif // CHROME_INSTALLER_MAC_APP_NETWORKCOMMUNICATION_H_