Web Animations API: Implement step-middle and steps(x, middle) timing functions.

Source/platform/animation/TimingFunctionTestHelperTest.cpp

Index: Source/platform/animation/TimingFunctionTestHelperTest.cpp
diff --git a/Source/platform/animation/TimingFunctionTestHelperTest.cpp b/Source/platform/animation/TimingFunctionTestHelperTest.cpp
index 2eefd12c0a0734add7f991a8bdd3cd1aff5c303a..eeda6030c55c792c958daa67ffa6787dcad9b0e4 100644
--- a/Source/platform/animation/TimingFunctionTestHelperTest.cpp
+++ b/Source/platform/animation/TimingFunctionTestHelperTest.cpp
@@ -118,7 +118,12 @@ TEST_F(TimingFunctionTestHelperTest, StepPrintTo)
         PrintToString(stepTimingStart),
         ::testing::MatchesRegex("step-start"));
 
-    RefPtr<TimingFunction> stepTimingCustom = StepsTimingFunction::create(5, false);
+    RefPtr<TimingFunction> stepTimingMiddle = StepsTimingFunction::preset(StepsTimingFunction::Middle);
+    EXPECT_THAT(
+        PrintToString(stepTimingMiddle),
+        ::testing::MatchesRegex("steps\\(1, middle\\)"));
+
+    RefPtr<TimingFunction> stepTimingCustom = StepsTimingFunction::create(5, StepsTimingFunction::StepAtEnd);
     EXPECT_THAT(
         PrintToString(stepTimingCustom),
         ::testing::MatchesRegex("steps\\(5, end\\)"));
@@ -158,7 +163,7 @@ TEST_F(TimingFunctionTestHelperTest, BaseOperatorEq)
     RefPtr<TimingFunction> cubicTiming1 = CubicBezierTimingFunction::preset(CubicBezierTimingFunction::EaseIn);
     RefPtr<TimingFunction> cubicTiming2 = CubicBezierTimingFunction::create(0.17, 0.67, 1, -1.73);
     RefPtr<TimingFunction> stepsTiming1 = StepsTimingFunction::preset(StepsTimingFunction::End);
-    RefPtr<TimingFunction> stepsTiming2 = StepsTimingFunction::create(5, true);
+    RefPtr<TimingFunction> stepsTiming2 = StepsTimingFunction::create(5, StepsTimingFunction::StepAtStart);
 
     RefPtr<ChainedTimingFunction> chainedTiming1 = ChainedTimingFunction::create();
     chainedTiming1->appendSegment(1.0, linearTiming.get());
@@ -232,15 +237,15 @@ TEST_F(TimingFunctionTestHelperTest, StepsOperatorEq)
     RefPtr<TimingFunction> stepsTimingEnd2 = StepsTimingFunction::preset(StepsTimingFunction::End);
     EXPECT_REFV_EQ(stepsTimingEnd1, stepsTimingEnd2);
 
-    RefPtr<TimingFunction> stepsTimingCustom1 = StepsTimingFunction::create(5, true);
-    RefPtr<TimingFunction> stepsTimingCustom2 = StepsTimingFunction::create(5, false);
-    RefPtr<TimingFunction> stepsTimingCustom3 = StepsTimingFunction::create(7, true);
-    RefPtr<TimingFunction> stepsTimingCustom4 = StepsTimingFunction::create(7, false);
+    RefPtr<TimingFunction> stepsTimingCustom1 = StepsTimingFunction::create(5, StepsTimingFunction::StepAtStart);
+    RefPtr<TimingFunction> stepsTimingCustom2 = StepsTimingFunction::create(5, StepsTimingFunction::StepAtEnd);
+    RefPtr<TimingFunction> stepsTimingCustom3 = StepsTimingFunction::create(7, StepsTimingFunction::StepAtStart);
+    RefPtr<TimingFunction> stepsTimingCustom4 = StepsTimingFunction::create(7, StepsTimingFunction::StepAtEnd);
 
-    EXPECT_REFV_EQ(stepsTimingCustom1, StepsTimingFunction::create(5, true));
-    EXPECT_REFV_EQ(stepsTimingCustom2, StepsTimingFunction::create(5, false));
-    EXPECT_REFV_EQ(stepsTimingCustom3, StepsTimingFunction::create(7, true));
-    EXPECT_REFV_EQ(stepsTimingCustom4, StepsTimingFunction::create(7, false));
+    EXPECT_REFV_EQ(stepsTimingCustom1, StepsTimingFunction::create(5, StepsTimingFunction::StepAtStart));
+    EXPECT_REFV_EQ(stepsTimingCustom2, StepsTimingFunction::create(5, StepsTimingFunction::StepAtEnd));
+    EXPECT_REFV_EQ(stepsTimingCustom3, StepsTimingFunction::create(7, StepsTimingFunction::StepAtStart));
+    EXPECT_REFV_EQ(stepsTimingCustom4, StepsTimingFunction::create(7, StepsTimingFunction::StepAtEnd));
 
     NE_HELPER(v);
     NE_HELPER_APPEND(v, stepsTimingStart1);
@@ -255,7 +260,7 @@ TEST_F(TimingFunctionTestHelperTest, StepsOperatorEq)
 TEST_F(TimingFunctionTestHelperTest, StepsOperatorEqReflectivity)
 {
     RefPtr<TimingFunction> stepsA = StepsTimingFunction::preset(StepsTimingFunction::Start);
-    RefPtr<TimingFunction> stepsB = StepsTimingFunction::create(1, true);
+    RefPtr<TimingFunction> stepsB = StepsTimingFunction::create(1, StepsTimingFunction::StepAtStart);
     EXPECT_REFV_NE(stepsA, stepsB);
     EXPECT_REFV_NE(stepsB, stepsA);
 }