Implement the file chooser as a new resource "host"

ppapi/shared_impl/ppb_file_ref_shared.cc

 // Copyright (c) 2012 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 "ppapi/shared_impl/ppb_file_ref_shared.h"
 
 #include "base/logging.h"
 #include "ppapi/shared_impl/var.h"
 
 namespace ppapi {
 
 PPB_FileRef_Shared::PPB_FileRef_Shared(ResourceObjectType type,
                                        const PPB_FileRef_CreateInfo& info)
     : Resource(type, info.resource),
       create_info_(info) {
   if (type == OBJECT_IS_IMPL) {
     // Resource's constructor assigned a PP_Resource, so we can fill out our
     // host resource now.
     create_info_.resource = host_resource();
-    DCHECK(!create_info_.resource.is_null());
   }
 }
 
 PPB_FileRef_Shared::~PPB_FileRef_Shared() {
 }
 
 thunk::PPB_FileRef_API* PPB_FileRef_Shared::AsPPB_FileRef_API() {
   return this;
 }
 
@@ skipping 15 matching lines @@
     path_var_ = new StringVar(create_info_.path);
   }
   return path_var_->GetPPVar();
 }
 
 const PPB_FileRef_CreateInfo& PPB_FileRef_Shared::GetCreateInfo() const {
   return create_info_;
 }
 
 }  // namespace ppapi