[Cleanup] Remove a reference to the FILE thread.

chrome/browser/metrics/antivirus_metrics_provider_win_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/metrics/antivirus_metrics_provider_win.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
@@ skipping 91 matching lines @@
 
  private:
   DISALLOW_COPY_AND_ASSIGN(AntiVirusMetricsProviderTest);
 };
 
 // TODO(crbug.com/682286): Flaky on windows 10.
 TEST_P(AntiVirusMetricsProviderTest, DISABLED_GetMetricsFullName) {
   ASSERT_TRUE(thread_checker_.CalledOnValidThread());
   base::HistogramTester histograms;
   SetFullNamesFeatureEnabled(expect_unhashed_value_);
-  // Make sure the I/O is happening on the FILE thread by disallowing it on
-  // the main thread.
+  // Make sure the I/O is happening on a valid thread by disallowing it on the
+  // main thread.
   bool previous_value = base::ThreadRestrictions::SetIOAllowed(false);
   provider_->GetAntiVirusMetrics(
       base::Bind(&AntiVirusMetricsProviderTest::GetMetricsCallback,
                  weak_ptr_factory_.GetWeakPtr()));
   scoped_task_environment_.RunUntilIdle();
   EXPECT_TRUE(got_results_);
   base::ThreadRestrictions::SetIOAllowed(previous_value);
 
   AntiVirusMetricsProvider::ResultCode expected_result =
       AntiVirusMetricsProvider::RESULT_SUCCESS;
@@ skipping 21 matching lines @@
       {"Trustwave AV 3_0_2547", "Trustwave AV"},
       {"nProtect Anti-Virus/Spyware V4.0", "nProtect Anti-Virus/Spyware"},
       {"ESET NOD32 Antivirus 9.0.349.15P", "ESET NOD32 Antivirus"}};
 
   for (const auto testcase : testcases) {
     auto output =
         AntiVirusMetricsProvider::TrimVersionOfAvProductName(testcase.input);
     EXPECT_STREQ(testcase.output, output.c_str());
   }
 }