Bug 1717312 - clear mapped values if we're not animating any more r=emilio

Differential Revision: https://phabricator.services.mozilla.com/D188712

dom/smil/SMILCSSProperty.cpp

@@ -101,9 +101,7 @@ nsresult SMILCSSProperty::SetAnimValue(const SMILValue& aValue) {
 }
 
 void SMILCSSProperty::ClearAnimValue() {
-  // Put empty string in override style for our property
-  mElement->SMILOverrideStyle()->SetPropertyValue(mPropID, ""_ns, nullptr,
-                                                  IgnoreErrors());
+  mElement->SMILOverrideStyle()->ClearSMILValue(mPropID);
 }
 
 // Based on http://www.w3.org/TR/SVG/propidx.html

dom/svg/SVGElement.cpp

@@ -1507,8 +1507,13 @@ void SVGElement::DidAnimateLength(uint8_t aAttrEnum) {
     // We don't map use element width/height currently. We can remove this
     // test when we do.
     if (propId != eCSSProperty_UNKNOWN) {
+      auto lengthInfo = GetLengthInfo();
+      if (lengthInfo.mValues[aAttrEnum].IsAnimated()) {
         SMILOverrideStyle()->SetSMILValue(propId,
-                                        GetLengthInfo().mValues[aAttrEnum]);
+                                          lengthInfo.mValues[aAttrEnum]);
+      } else {
+        SMILOverrideStyle()->ClearSMILValue(propId);
+      }
     }
   }
 
@@ -1711,8 +1716,13 @@ void SVGElement::DidAnimatePathSegList() {
 
   // Notify style we have to update the d property because of SMIL animation.
   if (name == nsGkAtoms::d) {
+    auto* animPathSegList = GetAnimPathSegList();
+    if (animPathSegList->IsAnimating()) {
       SMILOverrideStyle()->SetSMILValue(nsCSSPropertyID::eCSSProperty_d,
-                                      *GetAnimPathSegList());
+                                        *animPathSegList);
+    } else {
+      SMILOverrideStyle()->ClearSMILValue(nsCSSPropertyID::eCSSProperty_d);
+    }
   }
 
   DidAnimateAttribute(kNameSpaceID_None, name);

layout/style/nsDOMCSSAttrDeclaration.h

@@ -55,6 +55,10 @@ class nsDOMCSSAttributeDeclaration final : public nsDOMCSSDeclaration {
                         const SVGAnimatedLength& aLength);
   nsresult SetSMILValue(const nsCSSPropertyID,
                         const mozilla::SVGAnimatedPathSegList& aPath);
+  void ClearSMILValue(const nsCSSPropertyID aPropID) {
+    // Put empty string in override style for our property
+    SetPropertyValue(aPropID, ""_ns, nullptr, mozilla::IgnoreErrors());
+  }
 
   void SetPropertyValue(const nsCSSPropertyID aPropID, const nsACString& aValue,
                         nsIPrincipal* aSubjectPrincipal,

testing/web-platform/tests/svg/animations/scripted/clear-mapped-animation.svg

@@ -0,0 +1,17 @@
+<svg class="reftest-wait" onload="load()" xmlns="http://www.w3.org/2000/svg"
+  xmlns:html="http://www.w3.org/1999/xhtml">
+  <html:link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1717312"/>
+  <html:script src="/common/reftest-wait.js"/>
+  <html:script src="/common/rendering-utils.js"/>
+  <html:link rel="match" href="../../embedded/reference/green-rect-100x100.svg"/>
+  <rect id="r" width="100" height="50" fill="green">
+    <animate attributeName="height" values="0" dur="20ms"/>
+  </rect>
+  <script>
+    function load() {
+      document.documentElement.setCurrentTime(1);
+      document.getElementById("r").setAttribute("height", 100);
+      waitForAtLeastOneFrame().then(takeScreenshot);
+    }
+  </script>
+</svg>