TestBrowserThreads must outlive TestProfiles and TestProfileManagers

chrome/browser/sessions/session_restore_stats_collector_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/sessions/session_restore_stats_collector.h"
 
 #include <stddef.h>
 #include <utility>
 
 #include "base/macros.h"
@@ skipping 278 matching lines @@
     stats_collector_->DeferTab(controller);
   }
 
   // Inputs to the stats collector. Reset prior to each test.
   base::SimpleTestTickClock* test_tick_clock_;
   std::vector<RestoredTab> restored_tabs_;
 
   // Infrastructure needed for using the TestWebContentsFactory. These are
   // initialized once by the fixture and reused across unittests.
   base::MessageLoop message_loop_;
+  content::TestBrowserThread ui_thread_;
+  // |ui_thread_| needs to still be alive when |testing_profile_| is destroyed.
   TestingProfile testing_profile_;
-  content::TestBrowserThread ui_thread_;
 
   // A new web contents factory is generated per test. This automatically cleans
   // up any tabs created by previous tests.
   std::unique_ptr<content::TestWebContentsFactory> test_web_contents_factory_;
 
   // These are recreated for each test. The reporting delegate allows the test
   // to observe the behaviour of the SessionRestoreStatsCollector under test.
   PassthroughStatsReportingDelegate* passthrough_reporting_delegate_;
   TestSessionRestoreStatsCollector* stats_collector_;
 
@@ skipping 320 matching lines @@
   mock_reporting_delegate.ExpectReportTabLoaderStatsCalled(2, 1, 1, 0, 0, 0, 0,
                                                            1);
   mock_reporting_delegate.EnsureNoUnexpectedCalls();
 
   // Destroy the background tab. The collector should release itself.
   Tick();  // 3 ms.
   GenerateWebContentsDestroyed(1);
   mock_reporting_delegate.ExpectReportStatsCollectorDeathCalled();
   mock_reporting_delegate.EnsureNoUnexpectedCalls();
 }