Removed redundant PrintingUIWebContentsObserver.

chrome/browser/printing/print_job_worker.h

 // Copyright (c) 2012 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_PRINT_JOB_WORKER_H_
 #define CHROME_BROWSER_PRINTING_PRINT_JOB_WORKER_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 114 matching lines @@
 
   // Reports settings back to owner_.
   void GetSettingsDone(PrintingContext::Result result);
 
   // Use the default settings. When using GTK+ or Mac, this can still end up
   // displaying a dialog. So this needs to happen from the UI thread on these
   // systems.
   void UseDefaultSettings();
 
   // Printing context delegate.
-  scoped_ptr<PrintingContext::Delegate,
-             content::BrowserThread::DeleteOnUIThread>
-      printing_context_delegate_;
+  scoped_ptr<PrintingContext::Delegate> printing_context_delegate_;
 
   // Information about the printer setting.
   scoped_ptr<PrintingContext> printing_context_;
 
   // The printed document. Only has read-only access.
   scoped_refptr<PrintedDocument> document_;
 
   // The print destination, may be NULL.
   scoped_refptr<PrintDestinationInterface> destination_;
 
@@ skipping 12 matching lines @@
 
   // Used to generate a WeakPtr for callbacks.
   base::WeakPtrFactory<PrintJobWorker> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PrintJobWorker);
 };
 
 }  // namespace printing
 
 #endif  // CHROME_BROWSER_PRINTING_PRINT_JOB_WORKER_H_