Web Animations: Reduce duplication of Timing defaults.

Source/core/animation/TimedItemCalculationsTest.cpp

Index: Source/core/animation/TimedItemCalculationsTest.cpp
diff --git a/Source/core/animation/TimedItemCalculationsTest.cpp b/Source/core/animation/TimedItemCalculationsTest.cpp
index 3df1531f020224ccdec45ab84514afdf4c8c8e2d..b4ab9a5dca1dbdd5da7cadad9bc0a281ea2588d1 100644
--- a/Source/core/animation/TimedItemCalculationsTest.cpp
+++ b/Source/core/animation/TimedItemCalculationsTest.cpp
@@ -189,7 +189,7 @@ TEST(AnimationTimedItemCalculationsTest, TransformedTime)
     EXPECT_EQ(10, calculateTransformedTime(1, 20, 12, timing));
 
     // PlaybackDirectionReverse
-    timing.timingFunction = nullptr;
+    timing.timingFunction = Timing::defaults().timingFunction;
     timing.direction = Timing::PlaybackDirectionReverse;
     EXPECT_EQ(8, calculateTransformedTime(0, 20, 12, timing));
     EXPECT_EQ(8, calculateTransformedTime(1, 20, 12, timing));