Adding a reverse function to the TimingFunctions and tests to prove it works.

Source/core/platform/animation/TimingFunctionTest.cpp

 /*
  * Copyright (c) 2013, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 46 matching lines @@
             EXPECT_REFV_NE(v[i].second, v[j].second) \
                 << v[i].first \
                 << " (" << ::testing::PrintToString(*v[i].second.get()) << ")" \
                 << "  ==  " \
                 << v[j].first \
                 << " (" << ::testing::PrintToString(*v[j].second.get()) << ")" \
                 << "\n"; \
         } \
     }
 
-
 using namespace WebCore;
 
 namespace {
 
 class TimingFunctionTest : public ::testing::Test {
 protected:
     virtual void SetUp()
     {
         // Needed for ChainedTimingFunction support
         RuntimeEnabledFeatures::setWebAnimationsEnabled(true);
@@ skipping 175 matching lines @@
     EXPECT_REFV_EQ(chainedMixed1, chainedMixed3);
     EXPECT_REFV_NE(chainedMixed1, chainedSingleCubic1);
     EXPECT_REFV_NE(chainedMixed1, chainedSingleLinear1);
 
     RefPtr<ChainedTimingFunction> chainedMixed4 = ChainedTimingFunction::create();
     chainedMixed4->appendSegment(0.20, chainedSingleLinear1.get()); // Different offset
     chainedMixed4->appendSegment(1.0, cubicTiming1.get());
     EXPECT_REFV_NE(chainedMixed1, chainedMixed4);
 }
 
+TEST_F(TimingFunctionTest, LinearReverse)
+{
+    RefPtr<TimingFunction> linearTiming = LinearTimingFunction::create();
+    EXPECT_REFV_EQ(linearTiming, linearTiming->reverse());
+}
+
+TEST_F(TimingFunctionTest, CubicReverse)
+{
+    RefPtr<TimingFunction> cubicEaseInTiming = CubicBezierTimingFunction::preset(CubicBezierTimingFunction::EaseIn);
+    RefPtr<TimingFunction> cubicEaseOutTiming = CubicBezierTimingFunction::preset(CubicBezierTimingFunction::EaseOut);
+    RefPtr<TimingFunction> cubicEaseInOutTiming = CubicBezierTimingFunction::preset(CubicBezierTimingFunction::EaseInOut);
+
+    EXPECT_REFV_EQ(cubicEaseOutTiming, cubicEaseInTiming->reverse());
+    EXPECT_REFV_EQ(cubicEaseInTiming, cubicEaseOutTiming->reverse());
+    EXPECT_REFV_EQ(cubicEaseInOutTiming, cubicEaseInOutTiming->reverse());
+
+    RefPtr<TimingFunction> cubicCustomTiming = CubicBezierTimingFunction::create(0.17, 0.67, 1, -1.73);
+    RefPtr<TimingFunction> cubicCustomTimingReversed = CubicBezierTimingFunction::create(0.17, 0.67, 1, -1.73);
+    EXPECT_REFV_EQ(cubicCustomTimingReversed, cubicCustomTiming->reverse());
+}
+
+TEST_F(TimingFunctionTest, StepReverse)
+{
+    RefPtr<TimingFunction> stepTimingStart = StepsTimingFunction::preset(StepsTimingFunction::Start);
+    RefPtr<TimingFunction> stepTimingEnd = StepsTimingFunction::preset(StepsTimingFunction::End);
+
+    EXPECT_REFV_EQ(stepTimingEnd, stepTimingStart->reverse());
+    EXPECT_REFV_EQ(stepTimingStart, stepTimingEnd->reverse());
+
+    RefPtr<TimingFunction> stepTimingCustom = StepsTimingFunction::create(5, false);
+    RefPtr<TimingFunction> stepTimingCustomReversed = StepsTimingFunction::create(5, true);
+    EXPECT_REFV_EQ(stepTimingCustomReversed, stepTimingCustom);
+}
+
+TEST_F(TimingFunctionTest, ChainedReverse)
+{
+    RefPtr<TimingFunction> linearTiming = LinearTimingFunction::create();
+    RefPtr<ChainedTimingFunction> chainedLinearSingle = ChainedTimingFunction::create();
+    chainedLinearSingle->appendSegment(1.0, linearTiming.get());
+    EXPECT_REFV_EQ(chainedLinearSingle, chainedLinearSingle->reverse());
+
+    RefPtr<TimingFunction> cubicEaseInTiming = CubicBezierTimingFunction::preset(CubicBezierTimingFunction::EaseIn);
+    RefPtr<TimingFunction> cubicEaseOutTiming = CubicBezierTimingFunction::preset(CubicBezierTimingFunction::EaseOut);
+
+    RefPtr<ChainedTimingFunction> chainedMixed = ChainedTimingFunction::create();
+    chainedMixed->appendSegment(0.75, chainedLinearSingle.get());
+    chainedMixed->appendSegment(1.0, cubicEaseInTiming.get());
+
+    RefPtr<ChainedTimingFunction> chainedMixedReversed = ChainedTimingFunction::create();
+    chainedMixed->appendSegment(0.25, cubicEaseOutTiming.get());
+    chainedMixed->appendSegment(1.0, chainedLinearSingle.get());
+
+    EXPECT_REFV_EQ(chainedMixed, chainedMixedReversed);
+}
+
 } // namespace