Add forEach() to CSSVariablesMap

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 9a18d3e1ae0993029e654458ef3012d8c4474731..89b9355d0c018ef76dda3faf8ced4f1011432f9b 100644
--- a/Source/core/css/CSSComputedStyleDeclaration.cpp
+++ b/Source/core/css/CSSComputedStyleDeclaration.cpp
@@ -3063,6 +3063,36 @@ void CSSComputedStyleDeclaration::clearVariables(ExceptionState& es)
     es.throwDOMException(NoModificationAllowedError);
 }
 
+CSSComputedStyleDeclaration::ComputedCSSVariablesIterator::ComputedCSSVariablesIterator(const HashMap<AtomicString, String>* variables)
+    : m_active(variables)
+{
+    ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
+    if (m_active) {
+        m_it = variables->begin();
+        m_end = variables->end();
+    }
+}
+
+void CSSComputedStyleDeclaration::ComputedCSSVariablesIterator::advance()
+{
+    ASSERT(m_active);
+    ++m_it;
+    m_active = !atEnd();
+}
+
+AtomicString CSSComputedStyleDeclaration::ComputedCSSVariablesIterator::name() const
+{
+    ASSERT(m_active);
+    return m_it->key;
+}
+
+String CSSComputedStyleDeclaration::ComputedCSSVariablesIterator::value() const
+{
+    ASSERT(m_active);
+    return m_it->value;
+}
+
+
 PassRefPtr<CSSValueList> CSSComputedStyleDeclaration::getBackgroundShorthandValue() const
 {
     static const CSSPropertyID propertiesBeforeSlashSeperator[5] = { CSSPropertyBackgroundColor, CSSPropertyBackgroundImage,