Migrate mac installer to delegate-driven model

chrome/installer/mac/app/MainDelegate.h

Index: chrome/installer/mac/app/MainDelegate.h
diff --git a/chrome/installer/mac/app/MainDelegate.h b/chrome/installer/mac/app/MainDelegate.h
new file mode 100644
index 0000000000000000000000000000000000000000..efbe36fe0b30d778a9b196c7e3cfc046d802aeff
--- /dev/null
+++ b/chrome/installer/mac/app/MainDelegate.h
@@ -0,0 +1,23 @@
+// 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_MAINDELEGATE_H_
+#define CHROME_INSTALLER_MAC_APP_MAINDELEGATE_H_
+
+#import <Foundation/Foundation.h>
+
+#import "Downloader.h"
+#import "OmahaCommunication.h"
+
+// TODO: move this into the unpacking file when created
+@protocol UnpackDelegate
+- (void)onUnpackSuccess;
+@end
+
+@interface MainDelegate
+    : NSObject<OmahaCommunicationDelegate, DownloaderDelegate, UnpackDelegate>
+- (void)runApplication;
+@end
+
+#endif  // CHROME_INSTALLER_MAC_APP_MAINDELEGATE_H_