Web Animations: Fix error in clock update logic and re-enable timeline-time test

Source/core/animation/AnimationClockTest.cpp

Index: Source/core/animation/AnimationClockTest.cpp
diff --git a/Source/core/animation/AnimationClockTest.cpp b/Source/core/animation/AnimationClockTest.cpp
index 3ef0b58b4258519928c4abebda65b18b63e36d6d..83392ddd0d22203562208c0d9d21e539605484db 100644
--- a/Source/core/animation/AnimationClockTest.cpp
+++ b/Source/core/animation/AnimationClockTest.cpp
@@ -119,4 +119,17 @@ TEST_F(AnimationAnimationClockTest, UpdateTimeIsMonotonic)
     EXPECT_GE(150, animationClock.currentTime());
 }
 
+TEST_F(AnimationAnimationClockTest, CurrentTimeUpdatesTask)
+{
+    animationClock.updateTime(100);
+    EXPECT_EQ(100, animationClock.currentTime());
+
+    mockTime = 100;
+    AnimationClock::notifyTaskStart();
+    EXPECT_EQ(100, animationClock.currentTime());
+
+    mockTime = 150;
+    EXPECT_EQ(100, animationClock.currentTime());
+}
+
 }