Fix integration tests in src/chrome and src/extensions so that we can turn on IO thread checks wi...

chrome/browser/prefs/pref_functional_browsertest.cc

 // Copyright 2013 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 <string>
 
 #include "base/memory/ptr_util.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/threading/thread_restrictions.h"
 #include "chrome/browser/download/download_prefs.h"
 #include "chrome/browser/net/prediction_options.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_commands.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/test/base/in_process_browser_test.h"
 #include "chrome/test/base/testing_browser_process.h"
 #include "chrome/test/base/testing_profile.h"
@@ skipping 26 matching lines @@
          new content::DownloadTestObserverTerminal(
              download_manager,
              num_downloads,
              content::DownloadTestObserver::ON_DANGEROUS_DOWNLOAD_FAIL);
     return base::WrapUnique(downloads_observer);
   }
 };
 
 IN_PROC_BROWSER_TEST_F(PrefsFunctionalTest, TestDownloadDirPref) {
   ASSERT_TRUE(embedded_test_server()->Start());
+  base::ThreadRestrictions::ScopedAllowIO allow_io;
   base::ScopedTempDir new_download_dir;
   ASSERT_TRUE(new_download_dir.CreateUniqueTempDir());
 
   base::FilePath downloaded_pkg =
       new_download_dir.GetPath().AppendASCII("a_zip_file.zip");
 
   // Set pref to download in new_download_dir.
   browser()->profile()->GetPrefs()->SetFilePath(
       prefs::kDownloadDefaultDirectory, new_download_dir.GetPath());
 
@@ skipping 169 matching lines @@
   EXPECT_FALSE(prefs->GetBoolean(prefs::kAlternateErrorPagesEnabled));
   EXPECT_FALSE(prefs->GetBoolean(prefs::kSearchSuggestEnabled));
 }
 
 // Verify that we have some Local State prefs.
 IN_PROC_BROWSER_TEST_F(PrefsFunctionalTest, TestHaveLocalStatePrefs) {
   EXPECT_TRUE(g_browser_process->local_state()
                   ->GetPreferenceValues(PrefService::INCLUDE_DEFAULTS)
                   .get());
 }