M56: Print Preview: Fix handling of printers without capabilities.

chrome/browser/ui/webui/print_preview/printer_capabilities.cc

 // Copyright 2016 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.
 
 #include "chrome/browser/ui/webui/print_preview/printer_capabilities.h"
 
 #include <memory>
 #include <string>
 #include <utility>
 
@@ skipping 77 matching lines @@
   const auto printer_name_description =
       GetPrinterNameAndDescription(basic_info);
   const std::string& printer_name = printer_name_description.first;
   const std::string& printer_description = printer_name_description.second;
 
   auto printer_info = base::MakeUnique<base::DictionaryValue>();
   printer_info->SetString(kPrinterId, device_name);
   printer_info->SetString(kSettingPrinterName, printer_name);
   printer_info->SetString(kSettingPrinterDescription, printer_description);
 
-  std::unique_ptr<base::DictionaryValue> capabilities =
-      GetPrinterCapabilitiesOnBlockingPoolThread(device_name);
-  if (capabilities)
-    printer_info->Set(kPrinterCapabilities, std::move(capabilities));
+  auto capabilities = GetPrinterCapabilitiesOnBlockingPoolThread(device_name);
+  if (!capabilities)
+    capabilities = base::MakeUnique<base::DictionaryValue>();
+  printer_info->Set(kPrinterCapabilities, std::move(capabilities));
 
   return printer_info;
 }
 
 }  // namespace printing