Removed redundant PrintingUIWebContentsObserver.

chrome/browser/printing/printing_ui_web_contents_observer.h

-// Copyright 2013 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_PRINTING_PRINTING_UI_WEB_CONTENTS_OBSERVER_H_
-#define CHROME_BROWSER_PRINTING_PRINTING_UI_WEB_CONTENTS_OBSERVER_H_
-
-#include "base/basictypes.h"
-#include "content/public/browser/web_contents_observer.h"
-#include "ui/gfx/native_widget_types.h"
-
-namespace printing {
-
-// Wrapper used to keep track of the lifetime of a WebContents.
-// Lives on the UI thread.
-class PrintingUIWebContentsObserver : public content::WebContentsObserver {
- public:
-  explicit PrintingUIWebContentsObserver(content::WebContents* web_contents);
-  virtual ~PrintingUIWebContentsObserver();
-
-  // Return the parent NativeView of the observed WebContents.
-  gfx::NativeView GetParentView();
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(PrintingUIWebContentsObserver);
-};
-
-}  // namespace printing
-
-#endif  // CHROME_BROWSER_PRINTING_PRINTING_UI_WEB_CONTENTS_OBSERVER_H_