Update Native Client Authors to be Chromium Authors for the code moved from the

ppapi/native_client/src/shared/ppapi_proxy/browser_ppp_scrollbar.cc

-// Copyright (c) 2011 The Native Client Authors. All rights reserved.
+// Copyright (c) 2011 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 "native_client/src/shared/ppapi_proxy/browser_ppp_scrollbar.h"
 
 // Include file order cannot be observed because ppp_instance declares a
 // structure return type that causes an error on Windows.
 // TODO(sehr, brettw): fix the return types and include order in PPAPI.
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/c/pp_resource.h"
@@ skipping 47 matching lines @@
 const PPP_Scrollbar_Dev* BrowserScrollbar::GetInterface() {
   static const PPP_Scrollbar_Dev scrollbar_interface = {
     ValueChanged,
     OverlayChanged
   };
   return &scrollbar_interface;
 }
 
 }  // namespace ppapi_proxy