Migrate mac installer to delegate-driven model

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>
 
+// TODO: talk to @sdy about this class
+@interface NetworkCommunication : NSObject
+
 typedef void (^DataTaskCompletionHandler)(NSData*, NSURLResponse*, NSError*);
-typedef void (^DownloadTaskCompletionHandler)(NSURL*, NSURLResponse*, NSError*);
-
-@interface NetworkCommunication : NSObject
 
 @property(nonatomic, copy) NSMutableURLRequest* request;
 @property(nonatomic, copy) NSURLSession* session;
 @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.
 - (NSMutableURLRequest*)createRequestWithUrlAsString:(NSString*)urlString
                                           andXMLBody:(NSXMLDocument*)body;
 // Adds a data task to the run loop using the request instance variable.
-- (void)sendDataRequestWithCompletionHandler:
-    (DataTaskCompletionHandler)completionHandler;
+- (void)sendDataRequest;
 // Adds a download task to the run loop using the request instance variable.
 - (void)sendDownloadRequest;
 
 @end
 
 #endif  // CHROME_INSTALLER_MAC_APP_NETWORKCOMMUNICATION_H_