sync: annotate call to join SyncCoreThread to keep ThreadRestrictions happy.

chrome/browser/sync/glue/sync_backend_host.cc

 // Copyright (c) 2010 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 "build/build_config.h"
 
 #include <algorithm>
 
 #include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/task.h"
+#include "base/threading/thread_restrictions.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/browser_thread.h"
 #include "chrome/browser/net/gaia/token_service.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/autofill_model_associator.h"
 #include "chrome/browser/sync/glue/autofill_profile_model_associator.h"
 #include "chrome/browser/sync/glue/change_processor.h"
 #include "chrome/browser/sync/glue/database_model_worker.h"
@@ skipping 211 matching lines @@
   if (ui_worker())
     ui_worker()->Stop();
 
   // Stop will return once the thread exits, which will be after DoShutdown
   // runs. DoShutdown needs to run from core_thread_ because the sync backend
   // requires any thread that opened sqlite handles to relinquish them
   // personally. We need to join threads, because otherwise the main Chrome
   // thread (ui loop) can exit before DoShutdown finishes, at which point
   // virtually anything the sync backend does (or the post-back to
   // frontend_loop_ by our Core) will epically fail because the CRT won't be
-  // initialized. For now this only ever happens at sync-enabled-Chrome exit,
-  // meaning bug 1482548 applies to prolonged "waiting" that may occur in
-  // DoShutdown.
-  core_thread_.Stop();
+  // initialized.
+  // Since we are blocking the UI thread here, we need to turn ourselves in
+  // with the ThreadRestriction police.  For sentencing and how we plan to fix
+  // this, see bug 19757.
+  {
+    base::ThreadRestrictions::ScopedAllowIO allow_io;
+    core_thread_.Stop();
+  }
 
   registrar_.routing_info.clear();
   registrar_.workers[GROUP_DB] = NULL;
   registrar_.workers[GROUP_HISTORY] = NULL;
   registrar_.workers[GROUP_UI] = NULL;
   registrar_.workers[GROUP_PASSIVE] = NULL;
   registrar_.workers[GROUP_PASSWORD] = NULL;
   registrar_.workers.erase(GROUP_DB);
   registrar_.workers.erase(GROUP_HISTORY);
   registrar_.workers.erase(GROUP_UI);
@@ skipping 631 matching lines @@
 }
 
 void SyncBackendHost::Core::DeleteSyncDataFolder() {
   if (file_util::DirectoryExists(host_->sync_data_folder_path())) {
     if (!file_util::Delete(host_->sync_data_folder_path(), true))
       LOG(DFATAL) << "Could not delete the Sync Data folder.";
   }
 }
 
 }  // namespace browser_sync