Make PrinterProviderAPI a pure interface

chrome/browser/ui/webui/print_preview/extension_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_EXTENSION_PRINTER_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_PRINT_PREVIEW_EXTENSION_PRINTER_HANDLER_H_
 
 #include <string>
 
 #include "base/macros.h"
@@ skipping 55 matching lines @@
   // by |printer_description|.
   // |callback| is called with the converted data.
   void ConvertToPWGRaster(
       const scoped_refptr<base::RefCountedMemory>& data,
       const cloud_devices::CloudDeviceDescription& printer_description,
       const std::string& ticket,
       const gfx::Size& page_size,
       const RefCountedMemoryCallback& callback);
 
   // Sets print job document data and dispatches it using printerProvider API.
-  // TODO(tbarzic): Move PrinterProvider::PrintJob to it's own file so it can
-  // be forward-declared.
   void DispatchPrintJob(
       const PrinterHandler::PrintCallback& callback,
-      scoped_ptr<extensions::PrinterProviderAPI::PrintJob> print_job,
+      scoped_ptr<extensions::PrinterProviderPrintJob> print_job,
       const scoped_refptr<base::RefCountedMemory>& data);
 
   // Methods used as wrappers to callbacks for extensions::PrinterProviderAPI
   // methods, primarily so the callbacks can be bound to this class' weak ptr.
   // They just propagate results to callbacks passed to them.
   void WrapGetPrintersCallback(
       const PrinterHandler::GetPrintersCallback& callback,
       const base::ListValue& pritners,
       bool done);
   void WrapGetCapabilityCallback(
       const PrinterHandler::GetCapabilityCallback& callback,
       const std::string& destination_id,
       const base::DictionaryValue& capability);
   void WrapPrintCallback(const PrinterHandler::PrintCallback& callback,
                          bool success,
                          const std::string& status);
 
   content::BrowserContext* browser_context_;
 
   scoped_ptr<local_discovery::PWGRasterConverter> pwg_raster_converter_;
 
   base::WeakPtrFactory<ExtensionPrinterHandler> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionPrinterHandler);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_PRINT_PREVIEW_EXTENSION_PRINTER_HANDLER_H_