Fix flaky CertificateReportingServiceBrowserTest.DontSendOldReports test

chrome/browser/safe_browsing/certificate_reporting_service_browsertest.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/safe_browsing/certificate_reporting_service.h"
 
 #include "base/base_switches.h"
 #include "base/command_line.h"
 #include "base/macros.h"
 #include "base/test/histogram_tester.h"
@@ skipping 370 matching lines @@
       ReportExpectation::Failed({{"report1", RetryStatus::NOT_RETRIED}}));
 
   // Queued report should now be successfully sent.
   test_helper()->SetFailureMode(certificate_reporting_test_utils::
                                     ReportSendingResult::REPORTS_SUCCESSFUL);
   SendPendingReports();
   test_helper()->WaitForRequestsDestroyed(
       ReportExpectation::Successful({{"report1", RetryStatus::RETRIED}}));
 }
 
-// Failing on some Win and Mac buildbots.  See crbug.com/719138.
-#if defined(OS_WIN) || defined(OS_MACOSX)
-#define MAYBE_DontSendOldReports DISABLED_DontSendOldReports
-#else
-#define MAYBE_DontSendOldReports DontSendOldReports
-#endif
 // CertificateReportingService should ignore reports older than the report TTL.
 IN_PROC_BROWSER_TEST_F(CertificateReportingServiceBrowserTest,
-                       MAYBE_DontSendOldReports) {
+                       DontSendOldReports) {
   SetExpectedHistogramCountOnTeardown(5);
 
   base::SimpleTestClock* clock = new base::SimpleTestClock();
   base::Time reference_time = base::Time::Now();
   clock->SetNow(reference_time);
   factory()->SetClockForTesting(std::unique_ptr<base::Clock>(clock));
 
   // The service should ignore reports older than 24 hours.
   factory()->SetQueuedReportTTLForTesting(base::TimeDelta::FromHours(24));
 
@@ skipping 39 matching lines @@
   test_helper()->WaitForRequestsDestroyed(
       ReportExpectation::Failed({{"report2", RetryStatus::RETRIED}}));
 
   // Advance the clock 20 hours again so that report2 is 25 hours old and is
   // older than max age (24 hours).
   clock->Advance(base::TimeDelta::FromHours(20));
 
   // Send pending reports. report2 should be discarded since it's too old. No
   // other reports remain. If any report is sent, test teardown will catch it.
   SendPendingReports();
+
+  // Let all reports succeed and send a single report. This is to make sure
+  // that any (incorrectly) pending reports are dropped before the test tear
+  // down.
+  test_helper()->SetFailureMode(certificate_reporting_test_utils::
+                                    ReportSendingResult::REPORTS_SUCCESSFUL);
+  SendReport("report3");
+  test_helper()->WaitForRequestsDestroyed(
+      ReportExpectation::Successful({{"report3", RetryStatus::NOT_RETRIED}}));
 }
 
 // CertificateReportingService should drop old reports from its pending report
 // queue, if the queue is full.
 IN_PROC_BROWSER_TEST_F(CertificateReportingServiceBrowserTest,
                        DropOldReportsFromQueue) {
   SetExpectedHistogramCountOnTeardown(7);
 
   base::SimpleTestClock* clock = new base::SimpleTestClock();
   base::Time reference_time = base::Time::Now();
@@ skipping 144 matching lines @@
   test_helper()->WaitForRequestsCreated(
       ReportExpectation::Delayed({{"report1", RetryStatus::NOT_RETRIED}}));
 
   // Resume the delayed report and wait for it to complete.
   test_helper()->ResumeDelayedRequest();
   test_helper()->WaitForRequestsDestroyed(
       ReportExpectation::Delayed({{"report1", RetryStatus::NOT_RETRIED}}));
 }
 
 }  // namespace safe_browsing