Make font-size-adjust animatable.

Source/core/animation/EffectInput.cpp

Index: Source/core/animation/EffectInput.cpp
diff --git a/Source/core/animation/EffectInput.cpp b/Source/core/animation/EffectInput.cpp
index 7dbbf7cfe5498cef29b00d8bc7f75ef7915609b1..ad93440e0ff55816b15fb36814e6ecd28864a918 100644
--- a/Source/core/animation/EffectInput.cpp
+++ b/Source/core/animation/EffectInput.cpp
@@ -43,6 +43,19 @@
 
 namespace blink {
 
+static bool isValidValueForInterpolation(const CSSPropertyID& property, const CSSValue& value)
+{
+    const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
+
+    switch (property) {
+    case CSSPropertyFontSizeAdjust:
+        return primitiveValue.getDoubleValue(CSSPrimitiveValue::CSS_NUMBER) > 0;
+    default:
+        break;
+    }
+    return true;
+}
+
 PassRefPtrWillBeRawPtr<AnimationEffect> EffectInput::convert(Element* element, const Vector<Dictionary>& keyframeDictionaryVector, ExceptionState& exceptionState)
 {
     // FIXME: Remove the dependency on element.
@@ -51,6 +64,7 @@ PassRefPtrWillBeRawPtr<AnimationEffect> EffectInput::convert(Element* element, c
 
     StyleSheetContents* styleSheetContents = element->document().elementSheet().contents();
     StringKeyframeVector keyframes;
+    PropertySet invalidValueProperties;
     double lastOffset = 0;
 
     for (const auto& keyframeDictionary : keyframeDictionaryVector) {
@@ -104,9 +118,17 @@ PassRefPtrWillBeRawPtr<AnimationEffect> EffectInput::convert(Element* element, c
             String value;
             DictionaryHelper::get(keyframeDictionary, property, value);
             keyframe->setPropertyValue(id, value, styleSheetContents);
+
+            if (!isValidValueForInterpolation(id, *keyframe->propertyValue(id)))
+                invalidValueProperties.add(id);
         }
     }
 
+    for (CSSPropertyID property : invalidValueProperties) {
+        for (const auto& keyframe : keyframes)
+            keyframe->clearPropertyValue(property);
+    }
+
     RefPtrWillBeRawPtr<StringKeyframeEffectModel> keyframeEffectModel = StringKeyframeEffectModel::create(keyframes);
     if (keyframeEffectModel->hasSyntheticKeyframes()) {
         exceptionState.throwDOMException(NotSupportedError, "Partial keyframes are not supported.");