SequenceManager: Increase high resolution task test coverage

TBR=gab@chromium.org

Bug: 891670
Change-Id: I66e545c6bdbf04333cbd9178f8af9f8b2419e543
Reviewed-on: https://chromium-review.googlesource.com/c/1301456Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
Commit-Queue: Sami Kyöstilä <skyostil@chromium.org>
Cr-Commit-Position: refs/heads/master@{#603050}

base/task/sequence_manager/sequence_manager_impl_unittest.cc

@@ -3443,6 +3443,12 @@ TEST_P(SequenceManagerTest, HasPendingHighResolutionTasks) {
   RunLoop().RunUntilIdle();
   EXPECT_EQ(manager_->HasPendingHighResolutionTasks(), supports_high_res);
 
+  // Advancing to just before a pending low resolution task doesn't mean that we
+  // have pending high resolution work.
+  test_task_runner_->AdvanceMockTickClock(TimeDelta::FromMilliseconds(99));
+  RunLoop().RunUntilIdle();
+  EXPECT_FALSE(manager_->HasPendingHighResolutionTasks());
+
   test_task_runner_->AdvanceMockTickClock(TimeDelta::FromMilliseconds(100));
   RunLoop().RunUntilIdle();
   EXPECT_FALSE(manager_->HasPendingHighResolutionTasks());

base/task/sequence_manager/task_queue_impl.h

@@ -287,7 +287,7 @@ class BASE_EXPORT TaskQueueImpl {
 
    private:
     std::priority_queue<Task> queue_;
-    // Number of pending tasks in that need high resolution timing.
+    // Number of pending tasks in the queue that need high resolution timing.
     int pending_high_res_tasks_ = 0;
 
     DISALLOW_COPY_AND_ASSIGN(DelayedIncomingQueue);