Partial implementation of CSSVariablesMap for CSS Variables CSSOM

Source/core/css/StylePropertySet.cpp

Index: Source/core/css/StylePropertySet.cpp
diff --git a/Source/core/css/StylePropertySet.cpp b/Source/core/css/StylePropertySet.cpp
index 9a06b9f128981936664ddd3e1f1d0457ea592747..241d39e33124f33397ffcc781471eea1b29677a1 100644
--- a/Source/core/css/StylePropertySet.cpp
+++ b/Source/core/css/StylePropertySet.cpp
@@ -22,6 +22,7 @@
 #include "config.h"
 #include "core/css/StylePropertySet.h"
 
+#include "RuntimeEnabledFeatures.h"
 #include "core/css/CSSParser.h"
 #include "core/css/CSSValuePool.h"
 #include "core/css/CSSVariableValue.h"
@@ -121,6 +122,26 @@ PassRefPtr<CSSValue> StylePropertySet::getPropertyCSSValue(CSSPropertyID propert
     return propertyAt(foundPropertyIndex).value();
 }
 
+unsigned StylePropertySet::variableCount() const
+{
+    ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
+    unsigned count = 0;
+    for (unsigned i = 0; i < propertyCount(); ++i) {
+        if (propertyAt(i).id() == CSSPropertyVariable)
+            count++;
+    }
+    return count;
+}
+
+String StylePropertySet::variableValue(const AtomicString& name) const
+{
+    ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
+    size_t index = findVariableIndex(name);
+    if (index == notFound)
+        return String();
+    return toCSSVariableValue(propertyAt(index).value())->value();
+}
+
 bool MutableStylePropertySet::removeShorthandProperty(CSSPropertyID propertyID)
 {
     StylePropertyShorthand shorthand = shorthandForProperty(propertyID);
@@ -255,6 +276,27 @@ unsigned getIndexInShorthandVectorForPrefixingVariant(const CSSProperty& propert
     return indexOfShorthandForLonghand(prefixedShorthand, matchingShorthandsForLonghand(prefixingVariant));
 }
 
+bool MutableStylePropertySet::setVariableValue(const AtomicString& name, const String& value, bool important)
+{
+    ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
+    if (value.isEmpty())
+        return removeVariable(name);
+
+    size_t index = findVariableIndex(name);
+    if (index != notFound) {
+        CSSValue* cssValue = m_propertyVector.at(index).value();
+        if (toCSSVariableValue(cssValue)->value() == value)
+            return false;
+    }
+
+    CSSProperty property(CSSPropertyVariable, CSSVariableValue::create(name, value), important);
+    if (index == notFound)
+        m_propertyVector.append(property);
+    else
+        m_propertyVector.at(index) = property;
+    return true;
+}
+
 void MutableStylePropertySet::appendPrefixingVariantProperty(const CSSProperty& property)
 {
     m_propertyVector.append(property);
@@ -445,6 +487,17 @@ int StylePropertySet::findPropertyIndex(CSSPropertyID propertyID) const
     return -1;
 }
 
+size_t StylePropertySet::findVariableIndex(const AtomicString& name) const
+{
+    ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
+    for (int i = propertyCount() - 1; i >= 0; --i) {
+        const PropertyReference& property = propertyAt(i);
+        if (property.id() == CSSPropertyVariable && toCSSVariableValue(property.value())->name() == name)
+            return i;
+    }
+    return notFound;
+}
+
 CSSProperty* MutableStylePropertySet::findCSSPropertyWithID(CSSPropertyID propertyID)
 {
     int foundPropertyIndex = findPropertyIndex(propertyID);
@@ -489,6 +542,23 @@ void MutableStylePropertySet::removeEquivalentProperties(const CSSStyleDeclarati
         removeProperty(propertiesToRemove[i]);
 }
 
+bool MutableStylePropertySet::removeVariable(const AtomicString& name)
+{
+    ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
+    size_t index = findVariableIndex(name);
+    if (index == notFound)
+        return false;
+    m_propertyVector.remove(index);
+    return true;
+}
+
+bool MutableStylePropertySet::clearVariables()
+{
+    ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
+    CSSPropertyID variablesId = CSSPropertyVariable;
+    return removePropertiesInSet(&variablesId, 1);
+}
+
 PassRefPtr<MutableStylePropertySet> StylePropertySet::mutableCopy() const
 {
     return adoptRef(new MutableStylePropertySet(*this));
@@ -564,10 +634,9 @@ PassRefPtr<MutableStylePropertySet> MutableStylePropertySet::create(const CSSPro
 String StylePropertySet::PropertyReference::cssName() const
 {
     if (id() == CSSPropertyVariable) {
-        ASSERT(propertyValue()->isVariableValue());
         if (!propertyValue()->isVariableValue())
             return emptyString(); // Should not happen, but if it does, avoid a bad cast.
-        return "var-" + static_cast<const CSSVariableValue*>(propertyValue())->name();
+        return "var-" + toCSSVariableValue(propertyValue())->name();
     }
     return getPropertyNameString(id());
 }