Add forEach() to CSSVariablesMap

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 3f84e58ee46f0e76140b808322d65e306dfb528b..78e5fe1621df7a6a18c4ba199da13535d9dcc726 100644
--- a/Source/core/css/StylePropertySet.cpp
+++ b/Source/core/css/StylePropertySet.cpp
@@ -284,8 +284,15 @@ bool MutableStylePropertySet::setVariableValue(const AtomicString& name, const S
         return removeVariable(name);
 
     size_t index = findVariableIndex(name);
-    if (index != notFound) {
-        CSSValue* cssValue = m_propertyVector.at(index).value();
+    if (index == notFound) {
+        VariablesIterators* iterators = activeVariablesIterators();
+        if (iterators) {
+            VariablesIterators::iterator end = iterators->end();
+            for (VariablesIterators::iterator it = iterators->begin(); it != end; ++it)
+                (*it)->addedVariable(name);
+        }
+    } else {
+        const CSSValue* cssValue = m_propertyVector.at(index).value();
         if (toCSSVariableValue(cssValue)->value() == value)
             return false;
     }
@@ -552,6 +559,12 @@ bool MutableStylePropertySet::removeVariable(const AtomicString& name)
     if (index == notFound)
         return false;
     m_propertyVector.remove(index);
+    VariablesIterators* iterators = activeVariablesIterators();
+    if (iterators) {
+        VariablesIterators::iterator end = iterators->end();
+        for (VariablesIterators::iterator it = iterators->begin(); it != end; ++it)
+            (*it)->removedVariable(name);
+    }
     return true;
 }
 
@@ -559,7 +572,93 @@ bool MutableStylePropertySet::clearVariables()
 {
     ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
     CSSPropertyID variablesId = CSSPropertyVariable;
-    return removePropertiesInSet(&variablesId, 1);
+    bool removed = removePropertiesInSet(&variablesId, 1);
+    if (removed) {
+        VariablesIterators* iterators = activeVariablesIterators();
+        if (iterators) {
+            VariablesIterators::iterator end = iterators->end();
+            for (VariablesIterators::iterator it = iterators->begin(); it != end; ++it)
+                (*it)->clearedVariables();
+        }
+    }
+    return removed;
+}
+
+PassRefPtr<MutableStylePropertySet::VariablesIterator> MutableStylePropertySet::VariablesIterator::create(MutableStylePropertySet* propertySet)
+{
+    ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
+    RefPtr<VariablesIterator> iterator = adoptRef(new VariablesIterator(propertySet));
+    const size_t propertyCount = propertySet->propertyCount();
+    size_t variableCount = 0;
+    iterator->m_remainingNames.resize(propertyCount);
+    for (int i = propertyCount; i--;) {
+        const PropertyReference& property = propertySet->propertyAt(i);
+        if (property.id() == CSSPropertyVariable)
+            iterator->m_remainingNames[variableCount++] = toCSSVariableValue(property.value())->name();
+    }
+    iterator->m_remainingNames.shrink(variableCount);
+
+    MutableStylePropertySet::VariablesIteratorsMap* map = MutableStylePropertySet::activeVariablesIteratorsMap();
+    if (map->contains(propertySet))
+        map->find(propertySet)->value.append(iterator);
+    else
+        map->add(propertySet, VariablesIterators()).iterator->value.append(iterator);
+
+    return iterator.release();
+}
+
+void MutableStylePropertySet::VariablesIterator::addedVariable(const AtomicString& name)
+{
+    ASSERT(!m_remainingNames.contains(name));
+    ASSERT(!m_newNames.contains(name));
+    m_newNames.append(name);
+}
+
+void MutableStylePropertySet::VariablesIterator::removedVariable(const AtomicString& name)
+{
+    size_t index = m_remainingNames.find(name);
+    if (index != notFound)
+        m_remainingNames.remove(index);
+    index = m_newNames.find(name);
+    if (index != notFound)
+        m_newNames.remove(index);
+}
+
+void MutableStylePropertySet::VariablesIterator::clearedVariables()
+{
+    m_remainingNames.clear();
+    m_newNames.clear();
+}
+
+void MutableStylePropertySet::VariablesIterator::advance()
+{
+    if (!atEnd())
+        m_remainingNames.removeLast();
+    if (!m_newNames.isEmpty()) {
+        m_remainingNames.appendVector(m_newNames);
+        m_newNames.clear();
+    }
+}
+
+MutableStylePropertySet::VariablesIterator::~VariablesIterator()
+{
+    MutableStylePropertySet::VariablesIterators& iterators = MutableStylePropertySet::activeVariablesIteratorsMap()->find(m_propertySet.get())->value;
+    iterators.remove(iterators.reverseFind(this));
+}
+
+MutableStylePropertySet::VariablesIterators* MutableStylePropertySet::activeVariablesIterators()
+{
+    VariablesIteratorsMap* map = activeVariablesIteratorsMap();
+    VariablesIteratorsMap::iterator it = map->find(this);
+    if (it == map->end())
+        return 0;
+    return &it->value;
+}
+
+MutableStylePropertySet::VariablesIteratorsMap* MutableStylePropertySet::activeVariablesIteratorsMap()
+{
+    DEFINE_STATIC_LOCAL(VariablesIteratorsMap, map, ());
+    return &map;
 }
 
 PassRefPtr<MutableStylePropertySet> StylePropertySet::mutableCopy() const
@@ -634,6 +733,11 @@ PassRefPtr<MutableStylePropertySet> MutableStylePropertySet::create(const CSSPro
     return adoptRef(new MutableStylePropertySet(properties, count));
 }
 
+MutableStylePropertySet::~MutableStylePropertySet()
+{
+    activeVariablesIteratorsMap()->remove(this);
+}
+
 String StylePropertySet::PropertyReference::cssName() const
 {
     if (id() == CSSPropertyVariable) {