[web-animations] updating timing should invalidate the effect

https://bugs.webkit.org/show_bug.cgi?id=246865

Reviewed by Dean Jackson.

Since timing properties affect how the effect value is computed, we need to invalidate
the effect when those properties change. It's pretty amazing that this wasn't caught by
an existing WPT, but implementing iterationComposite surfaced that issue.

* LayoutTests/imported/w3c/web-platform-tests/web-animations/animation-model/keyframe-effects/effect-value-iteration-composite-operation-expected.txt:
* Source/WebCore/animation/KeyframeEffect.cpp:
(WebCore::KeyframeEffect::animationDidChangeTimingProperties):

Canonical link: https://commits.webkit.org/255863@main

LayoutTests/imported/w3c/web-platform-tests/web-animations/animation-model/keyframe-effects/effect-value-iteration-composite-operation-expected.txt

@@ -30,5 +30,5 @@ PASS iteration composition of transform of matrix3d function
 PASS iteration composition of transform of rotate3d function
 PASS iteration composition starts with non-zero value animation
 PASS iteration composition with negative final value animation
-FAIL duration changes with an iteration composition operation of accumulate assert_equals: Animated style at 25s of the first iteration expected "12.5px" but got "25px"
+PASS duration changes with an iteration composition operation of accumulate
 

Source/WebCore/animation/KeyframeEffect.cpp

@@ -1808,6 +1808,8 @@ void KeyframeEffect::animationDidChangeTimingProperties()
         }
     } else if (canBeAccelerated())
         m_runningAccelerated = RunningAccelerated::NotStarted;
+
+    invalidate();
 }
 
 void KeyframeEffect::transformRelatedPropertyDidChange()