Fix DesktopEngagementServiceTest.TestTimeoutDiscount unittests

chrome/browser/metrics/desktop_engagement/desktop_engagement_service_unittest.cc

Index: chrome/browser/metrics/desktop_engagement/desktop_engagement_service_unittest.cc
diff --git a/chrome/browser/metrics/desktop_engagement/desktop_engagement_service_unittest.cc b/chrome/browser/metrics/desktop_engagement/desktop_engagement_service_unittest.cc
index 03e5e854c1eb9d2e3043db00d232d00b625bd158..fc92532e61303043cc43f12f5d2e7d951a15d666 100644
--- a/chrome/browser/metrics/desktop_engagement/desktop_engagement_service_unittest.cc
+++ b/chrome/browser/metrics/desktop_engagement/desktop_engagement_service_unittest.cc
@@ -148,13 +148,7 @@ TEST(DesktopEngagementServiceTest, TestAudioEvent) {
   histogram_tester.ExpectTotalCount("Session.TotalDuration", 1);
 }
 
-// Flaky on Mac Debug. See http://crbug.com/646758
-#if defined(OS_MACOSX)
-#define MAYBE_TestTimeoutDiscount DISABLED_TestTimeoutDiscount
-#else
-#define MAYBE_TestTimeoutDiscount TestTimeoutDiscount
-#endif
-TEST(DesktopEngagementServiceTest, MAYBE_TestTimeoutDiscount) {
+TEST(DesktopEngagementServiceTest, TestTimeoutDiscount) {
   base::MessageLoop loop(base::MessageLoop::TYPE_DEFAULT);
   base::HistogramTester histogram_tester;
   MockDesktopEngagementService instance;
@@ -174,11 +168,10 @@ TEST(DesktopEngagementServiceTest, MAYBE_TestTimeoutDiscount) {
   base::TimeTicks after_session_end = base::TimeTicks::Now();
 
   histogram_tester.ExpectTotalCount("Session.TotalDuration", 1);
-  // The recorded value should be shorter than the specified inactivity
-  // interval.
   base::Bucket bucket =
       histogram_tester.GetAllSamples("Session.TotalDuration")[0];
-  EXPECT_LE(
-    bucket.min + inactivity_interval,
-    (after_session_end - before_session_start).InSeconds());
+  int max_expected_value =
+      (after_session_end - before_session_start -
+       base::TimeDelta::FromSeconds(inactivity_interval)).ToInternalValue();

[Alexei Svitkine (slow), 2016/09/15 16:40:22]

If the unit is milliseconds, please convert explicitly to milliseconds rather
than to internal value.

[gayane -on leave until 09-2017, 2016/09/15 18:37:36]

Done.

+  EXPECT_LE(bucket.min, max_expected_value);
 }