Add onGetUsbPrinterInfoRequested event to printerProvider API.

extensions/browser/api/printer_provider_internal/printer_provider_internal_api_observer.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 EXTENSIONS_BROWSER_API_PRINTER_PROVIDER_INTERNAL_PRINTER_PROVIDER_INTERNAL_API_OBSERVER_H_
 #define EXTENSIONS_BROWSER_API_PRINTER_PROVIDER_INTERNAL_PRINTER_PROVIDER_INTERNAL_API_OBSERVER_H_
 
 #include <vector>
 
 #include "extensions/common/api/printer_provider.h"
@@ skipping 35 matching lines @@
   // Used by chrome.printerProviderInternal API to report
   // chrome.printerProvider.onPrintRequested result returned by the extension
   // |extension|.
   // |request_id| is the request id passed to the original
   // chrome.printerProvider.onPrintRequested event.
   virtual void OnPrintResult(
       const Extension* extension,
       int request_id,
       core_api::printer_provider_internal::PrintError error) = 0;
 
+  // Used by chrome.printerProviderInternal API to report
+  // chrome.printerProvider.onGetUsbPrinterInfoRequested result returned by the
+  // extension |extension|.
+  // |request_id| is the request id passed to the original
+  // chrome.printerProvider.onGetUsbPrinterInfoRequested event.
+  virtual void OnGetUsbPrinterInfoResult(
+      const Extension* extension,
+      int request_id,
+      const core_api::printer_provider::PrinterInfo* printer_info) = 0;
+
  protected:
   virtual ~PrinterProviderInternalAPIObserver() {}
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_API_PRINTER_PROVIDER_INTERNAL_PRINTER_PROVIDER_INTERNAL_API_OBSERVER_H_