Refactor setup of background upload alert from MC to separate file.

ios/chrome/app/startup/background_upload_alert.h

Index: ios/chrome/app/startup/background_upload_alert.h
diff --git a/ios/chrome/app/startup/background_upload_alert.h b/ios/chrome/app/startup/background_upload_alert.h
new file mode 100644
index 0000000000000000000000000000000000000000..e48e2191cebcaf0864971d30ed80037e7f364734
--- /dev/null
+++ b/ios/chrome/app/startup/background_upload_alert.h
@@ -0,0 +1,16 @@
+// 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 IOS_CHROME_APP_STARTUP_BACKGROUND_UPLOAD_ALERT_H_
+#define IOS_CHROME_APP_STARTUP_BACKGROUND_UPLOAD_ALERT_H_
+
+#import <UIKit/UIKit.h>
+
+@interface BackgroundUploadAlert : NSObject
+
++ (void)setupBackgroundUploadAlert;
+
+@end
+
+#endif  // IOS_CHROME_APP_STARTUP_BACKGROUND_UPLOAD_ALERT_H_