[web-animations] provide a dedicated flag for KeyframeEffect.iteratio…

…nComposite

https://bugs.webkit.org/show_bug.cgi?id=240727

Patch by Antoine Quint <graouts@apple.com> on 2022-05-20
Reviewed by Dean Jackson.

Add a dedicated flag for the `KeyframeEffect.iterationComposite` property as
that property did not make it to Web Animations 1.0 and should not be enabled
together with `KeyframeEffect.composite`.

* Source/WTF/Scripts/Preferences/WebPreferencesExperimental.yaml:

* Source/WebCore/animation/KeyframeEffect.cpp:
(WebCore::KeyframeEffect::create):
* Source/WebCore/animation/KeyframeEffect.idl:

Canonical link: https://commits.webkit.org/250816@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@294579 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/WTF/Scripts/Preferences/WebPreferencesExperimental.yaml

@@ -1576,6 +1576,18 @@ WebAnimationsCustomFrameRateEnabled:
     WebCore:
       default: false
 
+WebAnimationsIterationCompositeEnabled:
+  type: bool
+  humanReadableName: "Web Animations iteration composite"
+  humanReadableDescription: "Support for the KeyframeEffect.iterationComposite property"
+  defaultValue:
+    WebKitLegacy:
+      default: false
+    WebKit:
+      default: false
+    WebCore:
+      default: false
+
 WebAnimationsMutableTimelinesEnabled:
   type: bool
   humanReadableName: "Web Animations mutable timelines"

Source/WebCore/animation/KeyframeEffect.cpp

@@ -519,7 +519,7 @@ ExceptionOr<Ref<KeyframeEffect>> KeyframeEffect::create(JSGlobalObject& lexicalG
                 keyframeEffectOptions.direction
             };
 
-            if (document.settings().webAnimationsCompositeOperationsEnabled()) {
+            if (document.settings().webAnimationsIterationCompositeEnabled()) {
                 keyframeEffect->setComposite(keyframeEffectOptions.composite);
                 keyframeEffect->setIterationComposite(keyframeEffectOptions.iterationComposite);
             }

Source/WebCore/animation/KeyframeEffect.idl

@@ -34,7 +34,7 @@ typedef USVString CSSOMString;
 
     attribute Element? target;
     attribute CSSOMString? pseudoElement;
-    [EnabledBySetting=WebAnimationsCompositeOperationsEnabled] attribute IterationCompositeOperation iterationComposite;
+    [EnabledBySetting=WebAnimationsIterationCompositeEnabled] attribute IterationCompositeOperation iterationComposite;
     [EnabledBySetting=WebAnimationsCompositeOperationsEnabled, ImplementedAs=bindingsComposite] attribute CompositeOperation composite;
     [Custom] sequence<object> getKeyframes();
     [CallWith=CurrentGlobalObject&CurrentDocument, ImplementedAs=setBindingsKeyframes] undefined setKeyframes(object? keyframes);