Forcibly clear worker ref counts on shutdown.

chrome/browser/chromeos/printing/printer_pref_manager_unittest.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/chromeos/printing/printer_pref_manager.h"
 
 #include <memory>
 #include <utility>
 
 #include "base/memory/ptr_util.h"
 #include "chrome/browser/chromeos/printing/printer_pref_manager_factory.h"
 #include "chrome/test/base/testing_profile.h"
+#include "content/public/test/test_browser_thread_bundle.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace chromeos {
 
 namespace {
 
 const char kPrinterId[] = "UUID-UUID-UUID-PRINTER";
 const char kUri[] = "ipps://printer.chromium.org/ipp/print";
 
 }  // namespace
 
 TEST(PrinterPrefManagerTest, AddPrinter) {
+  content::TestBrowserThreadBundle thread_bundle;
   std::unique_ptr<Profile> profile = base::MakeUnique<TestingProfile>();
   PrinterPrefManager* manager =
       PrinterPrefManagerFactory::GetForBrowserContext(profile.get());
 
   manager->RegisterPrinter(base::MakeUnique<Printer>(kPrinterId));
 
   auto printers = manager->GetPrinters();
   ASSERT_EQ(1U, printers.size());
   EXPECT_EQ(kPrinterId, printers[0]->id());
 }
 
 TEST(PrinterPrefManagerTest, UpdatePrinterAssignsId) {
+  content::TestBrowserThreadBundle thread_bundle;
   std::unique_ptr<Profile> profile = base::MakeUnique<TestingProfile>();
   PrinterPrefManager* manager =
       PrinterPrefManagerFactory::GetForBrowserContext(profile.get());
 
   manager->RegisterPrinter(base::MakeUnique<Printer>());
 
   auto printers = manager->GetPrinters();
   ASSERT_EQ(1U, printers.size());
   EXPECT_FALSE(printers[0]->id().empty());
 }
 
 TEST(PrinterPrefManagerTest, UpdatePrinter) {
+  content::TestBrowserThreadBundle thread_bundle;
   std::unique_ptr<Profile> profile = base::MakeUnique<TestingProfile>();
   PrinterPrefManager* manager =
       PrinterPrefManagerFactory::GetForBrowserContext(profile.get());
 
   manager->RegisterPrinter(base::MakeUnique<Printer>(kPrinterId));
   std::unique_ptr<Printer> updated_printer =
       base::MakeUnique<Printer>(kPrinterId);
   updated_printer->set_uri(kUri);
   manager->RegisterPrinter(std::move(updated_printer));
 
   auto printers = manager->GetPrinters();
   ASSERT_EQ(1U, printers.size());
   EXPECT_EQ(kUri, printers[0]->uri());
 }
 
 TEST(PrinterPrefManagerTest, RemovePrinter) {
+  content::TestBrowserThreadBundle thread_bundle;
   std::unique_ptr<Profile> profile = base::MakeUnique<TestingProfile>();
   PrinterPrefManager* manager =
       PrinterPrefManagerFactory::GetForBrowserContext(profile.get());
 
   manager->RegisterPrinter(base::MakeUnique<Printer>("OtherUUID"));
   manager->RegisterPrinter(base::MakeUnique<Printer>(kPrinterId));
   manager->RegisterPrinter(base::MakeUnique<Printer>());
 
   manager->RemovePrinter(kPrinterId);
 
   auto printers = manager->GetPrinters();
   ASSERT_EQ(2U, printers.size());
   EXPECT_NE(kPrinterId, printers.at(0)->id());
   EXPECT_NE(kPrinterId, printers.at(1)->id());
 }
 
 }  // namespace chromeos