[Mac] Delete old balloon and Notification Center notification implementations.

chrome/browser/ui/cocoa/notifications/balloon_view.h

-// Copyright (c) 2010 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_BROWSER_UI_COCOA_NOTIFICATIONS_BALLOON_VIEW_H_
-#define CHROME_BROWSER_UI_COCOA_NOTIFICATIONS_BALLOON_VIEW_H_
-
-#import <Cocoa/Cocoa.h>
-
-@interface BalloonWindow : NSWindow {
-}
-@end
-
-// This view class draws a frame around the HTML contents of a
-// notification balloon.
-@interface BalloonContentViewCocoa : NSView {
-}
-@end
-
-// This view class draws the shelf of a notification balloon,
-// containing the controls.
-@interface BalloonShelfViewCocoa : NSView {
-}
-@end
-
-// This view overlays the notification balloon on top. It is used to intercept
-// mouse input to prevent reordering of the other browser windows when clicking
-// on the notification balloon.
-@interface BalloonOverlayViewCocoa : NSView {
-}
-@end
-
-
-#endif  // CHROME_BROWSER_UI_COCOA_NOTIFICATIONS_BALLOON_VIEW_H_