Initial commit for Chrome metainstaller on Mac.

chrome/installer/mac/app/downloader.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_DOWNLOADER_H_
+#define CHROME_INSTALLER_MAC_APP_DOWNLOADER_H_
+
+#import <Foundation/Foundation.h>
+
+@interface Downloader : NSObject <NSXMLParserDelegate>
+
+// Calls parseXML and returns the first URL. Then calls appendFilename to form

[Elly Fong-Jones, 2016/07/06 15:22:02]

Comments in headers should be about the interface of the function - ie, what it
takes as inputs, what it returns as outputs, any side-effects it has. They
probably shouldn't describe the actual helper functions the function uses, since
then when the function body changes the comment will get stale.

+// complete download URLs.
+// TODO(ivan): check the URL's actually work ie. response is a 200/202 and

[Elly Fong-Jones, 2016/07/06 15:22:02]

TODOs should have your username in them, so this would be TODO(ivanhernandez)

+//             return the first working URL.
+- (NSURL*)parseOhamaResponseForChromeImageURLAndFilename:(NSData*)omahaResponseXML;
+
+// Writes the chrome image in memory to the user's download directory.
+- (void)writeChromeImageToDownloadsDirectory:(NSURL*)chromeURL;
+
+// Calls all the other methods in this class to download the latest version of
+// chrome.
+- (void)downloadChromeImageToDownloadsDirectory:(NSData*)responseXMLData;

[Elly Fong-Jones, 2016/07/06 15:22:02]

I think this is the only function that should really be publicly exposed here.
The others can be private helper functions that are only visible in the
corresponding .m file.

also, the argument needs to be documented/named more descriptively; what is it a
response from? maybe something like '(NSData*)omahaResponseXml'.

+
+@end
+
+#endif // CHROME_INSTALLER_MAC_APP_DOWNLOADER_H_