Web Animations CSS: Unfreeze AnimationClock if sampling timelines does not trigger style recalc

Source/core/animation/DocumentTimelineTest.cpp

Index: Source/core/animation/DocumentTimelineTest.cpp
diff --git a/Source/core/animation/DocumentTimelineTest.cpp b/Source/core/animation/DocumentTimelineTest.cpp
index 1b5f8f7ad6637a2782a69f14ba530173b9833b1f..897bab2dc4501fb24b02dfa733170f3cae8431eb 100644
--- a/Source/core/animation/DocumentTimelineTest.cpp
+++ b/Source/core/animation/DocumentTimelineTest.cpp
@@ -114,7 +114,6 @@ protected:
     {
         return DocumentTimeline::s_minimumDelay;
     }
-
 };
 
 TEST_F(CoreAnimationDocumentTimelineTest, EmptyKeyframeAnimation)
@@ -134,22 +133,56 @@ TEST_F(CoreAnimationDocumentTimelineTest, EmptyKeyframeAnimation)
     EXPECT_FLOAT_EQ(100, timeline->currentTime());
 }
 
-TEST_F(CoreAnimationDocumentTimelineTest, ZeroTimeAsPerfTime)
+TEST_F(CoreAnimationDocumentTimelineTest, EmptyTimelineDoesNotFreezeTime)
 {
-    timeline = DocumentTimeline::create(document.get());
+    timeline->serviceAnimations(100);
+    EXPECT_NE(100, timeline->currentTime());
+}
+
+TEST_F(CoreAnimationDocumentTimelineTest, EmptyPlayerDoesNotFreezeTime)
+{
+    timeline->play(0);
+    timeline->serviceAnimations(100);
+    EXPECT_NE(100, timeline->currentTime());
+}
+
+TEST_F(CoreAnimationDocumentTimelineTest, EmptyTargetDoesNotFreezeTime)
+{
+    timing.iterationDuration = 200;
+    timeline->play(Animation::create(0, KeyframeAnimationEffect::create(KeyframeAnimationEffect::KeyframeVector()), timing).get());
+    timeline->serviceAnimations(100);
+    EXPECT_NE(100, timeline->currentTime());
+}
 
+TEST_F(CoreAnimationDocumentTimelineTest, EmptyEffectDoesNotFreezeTime)
+{
+    timeline->play(Animation::create(element.get(), 0, timing).get());
+    timeline->serviceAnimations(100);
+    EXPECT_NE(100, timeline->currentTime());
+}
+
+TEST_F(CoreAnimationDocumentTimelineTest, FreezeTime)
+{
+    timeline->play(Animation::create(element.get(), KeyframeAnimationEffect::create(KeyframeAnimationEffect::KeyframeVector()), timing).get());
     timeline->serviceAnimations(100);
+    EXPECT_EQ(100, timeline->currentTime());
+}
+
+TEST_F(CoreAnimationDocumentTimelineTest, ZeroTime)
+{
+    timeline = DocumentTimeline::create(document.get());
+
+    document->animationClock().updateTime(100);
     EXPECT_TRUE(isNull(timeline->currentTime()));
 
-    timeline->serviceAnimations(200);
+    document->animationClock().updateTime(200);
     EXPECT_TRUE(isNull(timeline->currentTime()));
 
     timeline->setZeroTime(300);
     document->animationClock().updateTime(300);
-    timeline->serviceAnimations(300);
     EXPECT_EQ(0, timeline->currentTime());
 
-    timeline->serviceAnimations(400);
+    document->animationClock().updateTime(400);
     EXPECT_EQ(100, timeline->currentTime());
 }
 
@@ -215,7 +248,6 @@ TEST_F(CoreAnimationDocumentTimelineTest, NumberOfActiveAnimations)
 
 TEST_F(CoreAnimationDocumentTimelineTest, DelayBeforeAnimationStart)
 {
-
     timing.hasIterationDuration = true;
     timing.iterationDuration = 2;
     timing.startDelay = 5;