Include USB printers in printer list as "provisional" devices.

chrome/browser/ui/webui/print_preview/printer_handler.h

 // Copyright 2015 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_WEBUI_PRINT_PREVIEW_PRINTER_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_PRINT_PREVIEW_PRINTER_HANDLER_H_
 
 #include <string>
 
 #include "base/callback.h"
@@ skipping 22 matching lines @@
 class PrinterHandler {
  public:
   using GetPrintersCallback =
       base::Callback<void(const base::ListValue& printers, bool done)>;
   using GetCapabilityCallback =
       base::Callback<void(const std::string& printer_id,
                           const base::DictionaryValue& capability)>;
   using PrintCallback =
       base::Callback<void(bool success, const std::string& error)>;
 
-  // Creates an instance of an PrinterHandler for extension printers.
-  static scoped_ptr<PrinterHandler> CreateForExtensionPrinters(
-      content::BrowserContext* browser_context);
-
   virtual ~PrinterHandler() {}
 
   // Cancels all pending requests.
   virtual void Reset() = 0;
 
   // Starts getting available printers.
   // |callback| should be called in the response to the request.
   virtual void StartGetPrinters(const GetPrintersCallback& callback) = 0;
 
   // Starts getting printing capability of the printer with the provided
@@ skipping 15 matching lines @@
       const std::string& destination_id,
       const std::string& capability,
       const base::string16& job_title,
       const std::string& ticket_json,
       const gfx::Size& page_size,
       const scoped_refptr<base::RefCountedMemory>& print_data,
       const PrintCallback& callback) = 0;
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_PRINT_PREVIEW_PRINTER_HANDLER_H_