Convert PpdCache and PpdProvider to TaskScheduler.

chromeos/printing/ppd_provider.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 "chromeos/printing/ppd_provider.h"
 
 #include <algorithm>
 #include <deque>
 #include <set>
 #include <unordered_map>
 #include <utility>
 #include <vector>
 
 #include "base/base64.h"
 #include "base/bind_helpers.h"
 #include "base/files/file.h"
 #include "base/files/file_util.h"
 #include "base/json/json_parser.h"
 #include "base/memory/ptr_util.h"
+#include "base/sequenced_task_runner.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_tokenizer.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/synchronization/lock.h"
 #include "base/task_runner_util.h"
+#include "base/task_scheduler/post_task.h"
 #include "base/threading/sequenced_task_runner_handle.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/time/time.h"
 #include "base/values.h"
 #include "chromeos/printing/ppd_cache.h"
 #include "chromeos/printing/printing_constants.h"
 #include "net/base/load_flags.h"
 #include "net/http/http_status_code.h"
 #include "net/url_request/url_fetcher.h"
 #include "net/url_request/url_fetcher_delegate.h"
@@ skipping 157 matching lines @@
     FT_PRINTERS,       // List of printers from a manufacturer.
     FT_PPD_INDEX,      // Master ppd index.
     FT_PPD,            // A Ppd file.
     FT_USB_DEVICES     // USB device id to canonical name map.
   };
 
   PpdProviderImpl(
       const std::string& browser_locale,
       scoped_refptr<net::URLRequestContextGetter> url_context_getter,
       scoped_refptr<PpdCache> ppd_cache,
-      scoped_refptr<base::SequencedTaskRunner> disk_task_runner,
       const PpdProvider::Options& options)
       : browser_locale_(browser_locale),
         url_context_getter_(url_context_getter),
         ppd_cache_(ppd_cache),
-        disk_task_runner_(disk_task_runner),
+        disk_task_runner_(base::CreateSequencedTaskRunnerWithTraits(
+            {base::TaskPriority::USER_BLOCKING,

[gab, 2017/06/19 15:13:22]

Are you sure this is USER_BLOCKING? It was previously using the FILE thread
which wasn't appropriate for user blocking work (was that a bug?)

[skau, 2017/06/19 23:31:08]

No.  This should have been USER_VISIBLE.  It is now fixed.

+             base::TaskShutdownBehavior::SKIP_ON_SHUTDOWN})),
         options_(options),
         weak_factory_(this) {}
 
   // Resolving manufacturers requires a couple of steps, because of
   // localization.  First we have to figure out what locale to use, which
   // involves grabbing a list of available locales from the server.  Once we
   // have decided on a locale, we go out and fetch the manufacturers map in that
   // localization.
   //
   // This means when a request comes in, we either queue it and start background
@@ skipping 774 matching lines @@
   ~PpdProviderImpl() override {}
 };
 
 }  // namespace
 
 // static
 scoped_refptr<PpdProvider> PpdProvider::Create(
     const std::string& browser_locale,
     scoped_refptr<net::URLRequestContextGetter> url_context_getter,
     scoped_refptr<PpdCache> ppd_cache,
-    scoped_refptr<base::SequencedTaskRunner> disk_task_runner,
     const PpdProvider::Options& options) {
-  return scoped_refptr<PpdProvider>(
-      new PpdProviderImpl(browser_locale, url_context_getter, ppd_cache,
-                          disk_task_runner, options));
+  return scoped_refptr<PpdProvider>(new PpdProviderImpl(
+      browser_locale, url_context_getter, ppd_cache, options));
 }
 }  // namespace printing
 }  // namespace chromeos