Fix typo and remove extra line break from TestMockTimeTaskRunner.

base/test/test_mock_time_task_runner.h

Index: base/test/test_mock_time_task_runner.h
diff --git a/base/test/test_mock_time_task_runner.h b/base/test/test_mock_time_task_runner.h
index dbd80ae13aa700be26042497b0db7ff3dbafe339..1a651f6f81e053945d15d4bd24b75ecda2509b91 100644
--- a/base/test/test_mock_time_task_runner.h
+++ b/base/test/test_mock_time_task_runner.h
@@ -33,7 +33,7 @@ class TickClock;
 //     turn call back into it (e.g., to post more tasks).
 //   - Tasks are stored in a priority queue, and executed in the increasing
 //     order of post time + delay.
-//   - It does not check for overflow when doing time arithmetic``. A sufficient
+//   - It does not check for overflow when doing time arithmetic. A sufficient
 //     condition for preventing overflows is to make sure that the sum of all
 //     posted task delays and fast-forward increments is still representable by
 //     a TimeDelta, and that adding this delta to the starting values of Time