Update PpdProvider threading model.

chrome/browser/ui/webui/settings/chromeos/cups_printers_handler.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/settings/chromeos/cups_printers_handler.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 65 matching lines @@
 
 CupsPrintersHandler::CupsPrintersHandler(content::WebUI* webui)
     : printer_discoverer_(nullptr),
       profile_(Profile::FromWebUI(webui)),
       weak_factory_(this) {
   base::FilePath ppd_cache_path;
   CHECK(
       base::PathService::Get(chrome::DIR_CHROMEOS_PPD_CACHE, &ppd_cache_path));
   ppd_provider_ = chromeos::printing::PpdProvider::Create(
       google_apis::GetAPIKey(), g_browser_process->system_request_context(),
+      content::BrowserThread::GetTaskRunnerForThread(
+          content::BrowserThread::FILE)
+          .get(),

[skau, 2016/11/09 00:01:09]

Why are you using the raw pointer instead of the smart pointer?

[Carlson, 2016/11/10 19:22:50]

Changed to scoped_refptr (see other comment)

       chromeos::printing::PpdCache::Create(ppd_cache_path));
 }
 
 CupsPrintersHandler::~CupsPrintersHandler() {}
 
 void CupsPrintersHandler::RegisterMessages() {
   web_ui()->RegisterMessageCallback(
       "getCupsPrintersList",
       base::Bind(&CupsPrintersHandler::HandleGetCupsPrintersList,
                  base::Unretained(this)));
@@ skipping 268 matching lines @@
                          *printers_list);
 }
 
 void CupsPrintersHandler::OnDiscoveryDone() {
   CallJavascriptFunction("cr.webUIListenerCallback",
                          base::StringValue("on-printer-discovery-done"));
 }
 
 }  // namespace settings
 }  // namespace chromeos