Export of internal Abseil changes.

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e09635c907d471ab46e14fb8091988c92cb4e78e by Abseil Team <absl-team@google.com>:

Fix syntax error in documentation '}' -> ')'

PiperOrigin-RevId: 215744854

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a9e2d036850748137355f4a07083f1052d5c3766 by Abseil Team <absl-team@google.com>:

WrapUnique's comment about avoiding explicit template specification
doesn't make clear what alternative there is when this hurts
readability. Add a comment about the approved alternative.

PiperOrigin-RevId: 215634917

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596b8ff41ff70b27bff3a2369038c0fe7d13ae85 by Greg Falcon <gfalcon@google.com>:

Allow for a small amount of slop in timeout tests, as not all OSs we support give us the perfect timing behavior we're testing for here.

PiperOrigin-RevId: 215615172
GitOrigin-RevId: e09635c907d471ab46e14fb8091988c92cb4e78e
Change-Id: I30721294bac86510a49bb7f405149fc74c532abb

1 files changed, 6 insertions, 3 deletions

diff --git a/absl/synchronization/notification_test.cc b/absl/synchronization/notification_test.cc
index 9b3b6a5a..d8708d55 100644
--- a/absl/synchronization/notification_test.cc
+++ b/absl/synchronization/notification_test.cc
@@ -71,10 +71,13 @@ static void BasicTests(bool notify_before_waiting, Notification* notification) {
       notification->WaitForNotificationWithTimeout(absl::Milliseconds(0)));
   EXPECT_FALSE(notification->WaitForNotificationWithDeadline(absl::Now()));
 
+  const absl::Duration delay = absl::Milliseconds(50);
+  // Allow for a slight early return, to account for quality of implementation
+  // issues on various platforms.
+  const absl::Duration slop = absl::Microseconds(200);
   absl::Time start = absl::Now();
-  EXPECT_FALSE(
-      notification->WaitForNotificationWithTimeout(absl::Milliseconds(50)));
-  EXPECT_LE(start + absl::Milliseconds(50), absl::Now());
+  EXPECT_FALSE(notification->WaitForNotificationWithTimeout(delay));
+  EXPECT_LE(start + delay, absl::Now() + slop);
 
   ThreadSafeCounter ready_counter;
   ThreadSafeCounter done_counter;