Make chromeos CUPS printing code namespaces consistent.

chrome/browser/ui/webui/print_preview/printer_backend_proxy_chromeos.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_backend_proxy.h"
 
 #include <memory>
 #include <vector>
 
 #include "base/bind_helpers.h"
@@ skipping 167 matching lines @@
       case chromeos::PrinterSetupResult::kMaxValue:
         NOTREACHED() << "This value is not expected";
         break;
     }
 
     // TODO(skau): Open printer settings if this is resolvable.
     cb.Run(nullptr);
   }
 
   chromeos::SyncedPrintersManager* prefs_;
-  scoped_refptr<chromeos::printing::PpdProvider> ppd_provider_;
+  scoped_refptr<chromeos::PpdProvider> ppd_provider_;
   std::unique_ptr<chromeos::PrinterConfigurer> printer_configurer_;
   base::WeakPtrFactory<PrinterBackendProxyChromeos> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PrinterBackendProxyChromeos);
 };
 
 }  // namespace
 
 std::unique_ptr<PrinterBackendProxy> PrinterBackendProxy::Create(
     Profile* profile) {
   return base::MakeUnique<PrinterBackendProxyChromeos>(profile);
 }
 
 }  // namespace printing