Partial implementation of CSSVariablesMap for CSS Variables CSSOM

Source/core/css/CSSComputedStyleDeclaration.cpp

Index: Source/core/css/CSSComputedStyleDeclaration.cpp
diff --git a/Source/core/css/CSSComputedStyleDeclaration.cpp b/Source/core/css/CSSComputedStyleDeclaration.cpp
index f0f308782671a9e52ec4b5d5cdc7ed8f2d1eacba..9f9bd4960164b8df95bbc7ba69329b3d78d0ad24 100644
--- a/Source/core/css/CSSComputedStyleDeclaration.cpp
+++ b/Source/core/css/CSSComputedStyleDeclaration.cpp
@@ -26,6 +26,7 @@
 
 #include "CSSPropertyNames.h"
 #include "FontFamilyNames.h"
+#include "RuntimeEnabledFeatures.h"
 #include "core/css/BasicShapeFunctions.h"
 #include "core/css/CSSArrayFunctionValue.h"
 #include "core/css/CSSAspectRatioValue.h"
@@ -3007,6 +3008,57 @@ void CSSComputedStyleDeclaration::setPropertyInternal(CSSPropertyID, const Strin
     ec = NO_MODIFICATION_ALLOWED_ERR;
 }
 
+const HashMap<AtomicString, String>* CSSComputedStyleDeclaration::variableMap() const
+{
+    ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
+    Node* styledNode = this->styledNode();
+    if (!styledNode)
+        return 0;
+    RefPtr<RenderStyle> style = styledNode->computedStyle(styledNode->isPseudoElement() ? NOPSEUDO : m_pseudoElementSpecifier);
+    if (!style)
+        return 0;
+    return style->variables();
+}
+
+unsigned CSSComputedStyleDeclaration::variableCount() const
+{
+    ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
+    const HashMap<AtomicString, String>* variables = variableMap();
+    if (!variables)
+        return 0;
+    return variables->size();
+}
+
+String CSSComputedStyleDeclaration::variableValue(const AtomicString& name) const
+{
+    ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
+    const HashMap<AtomicString, String>* variables = variableMap();
+    if (!variables)
+        return emptyString();
+    HashMap<AtomicString, String>::const_iterator it = variables->find(name);
+    if (it == variables->end())
+        return emptyString();
+    return it->value;
+}
+
+void CSSComputedStyleDeclaration::setVariableValue(const AtomicString&, const String&, ExceptionCode& ec)
+{
+    ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
+    ec = NO_MODIFICATION_ALLOWED_ERR;
+}
+
+bool CSSComputedStyleDeclaration::removeVariable(const AtomicString&)
+{
+    ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
+    return false;
+}
+
+void CSSComputedStyleDeclaration::clearVariables(ExceptionCode& ec)
+{
+    ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
+    ec = NO_MODIFICATION_ALLOWED_ERR;
+}
+
 PassRefPtr<CSSValueList> CSSComputedStyleDeclaration::getBackgroundShorthandValue() const
 {
     static const CSSPropertyID propertiesBeforeSlashSeperator[5] = { CSSPropertyBackgroundColor, CSSPropertyBackgroundImage,