[Mac] Organize all infobar files into chrome/browser/ui/cocoa/infobars/....

chrome/browser/ui/cocoa/infobar_gradient_view.h

Index: chrome/browser/ui/cocoa/infobar_gradient_view.h
===================================================================
--- chrome/browser/ui/cocoa/infobar_gradient_view.h	(revision 71658)
+++ chrome/browser/ui/cocoa/infobar_gradient_view.h	(working copy)
@@ -1,19 +0,0 @@
-// Copyright (c) 2009 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_INFOBAR_GRADIENT_VIEW_H_
-#define CHROME_BROWSER_UI_COCOA_INFOBAR_GRADIENT_VIEW_H_
-#pragma once
-
-#import "chrome/browser/ui/cocoa/vertical_gradient_view.h"
-
-#import <Cocoa/Cocoa.h>
-
-// A custom view that draws the background gradient for an infobar.
-@interface InfoBarGradientView : VerticalGradientView {
-}
-
-@end
-
-#endif  // CHROME_BROWSER_UI_COCOA_INFOBAR_GRADIENT_VIEW_H_