Forcibly clear worker ref counts on shutdown.

chrome/browser/browsing_data/browsing_data_counter_utils_unittest.cc

 // Copyright 2015 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/browsing_data/browsing_data_counter_utils.h"
 
 #include <string>
 #include <vector>
 
 #include "base/message_loop/message_loop.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/test/base/testing_browser_process.h"
 #include "chrome/test/base/testing_profile.h"
+#include "content/public/test/test_browser_thread_bundle.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 #if defined(ENABLE_EXTENSIONS)
 #include "base/strings/string_split.h"
 #include "chrome/browser/browsing_data/hosted_apps_counter.h"
 #endif
 
 class BrowsingDataCounterUtilsTest : public testing::Test {
  public:
   BrowsingDataCounterUtilsTest() {}
   ~BrowsingDataCounterUtilsTest() override {}
 
   TestingProfile* GetProfile() { return &profile_; }
 
  private:
-  base::MessageLoop loop_;
+  content::TestBrowserThreadBundle thread_bundle_;
   TestingProfile profile_;
 };
 
 #if defined(ENABLE_EXTENSIONS)
 // Tests the complex output of the hosted apps counter.
 TEST_F(BrowsingDataCounterUtilsTest, HostedAppsCounterResult) {
   HostedAppsCounter counter(GetProfile());
 
   // This test assumes that the strings are served exactly as defined,
   // i.e. that the locale is set to the default "en".
@@ skipping 26 matching lines @@
     HostedAppsCounter::HostedAppsResult result(
         &counter,
         apps.size(),
         examples);
 
     base::string16 output = GetChromeCounterTextFromResult(&result);
     EXPECT_EQ(output, base::ASCIIToUTF16(test_case.expected_output));
   }
 }
 #endif