Oilpan: tidy StylePropertySerializer's handling of GCed objects.

Source/core/css/StylePropertySerializer.cpp

Index: Source/core/css/StylePropertySerializer.cpp
diff --git a/Source/core/css/StylePropertySerializer.cpp b/Source/core/css/StylePropertySerializer.cpp
index e81a5aead2ebfba3714bcdfac3408d5992ff73bc..5eb0a3fea3fcf5d800f74bf91b700f01e7e06130 100644
--- a/Source/core/css/StylePropertySerializer.cpp
+++ b/Source/core/css/StylePropertySerializer.cpp
@@ -40,16 +40,16 @@ static bool isInitialOrInherit(const String& value)
 }
 
 StylePropertySerializer::StylePropertySetForSerializer::StylePropertySetForSerializer(const StylePropertySet& properties)
-    : m_propertySet(properties)
-    , m_allIndex(m_propertySet.findPropertyIndex(CSSPropertyAll))
+    : m_propertySet(&properties)
+    , m_allIndex(m_propertySet->findPropertyIndex(CSSPropertyAll))
     , m_needToExpandAll(false)
 {
     if (!hasAllProperty())
         return;
 
-    StylePropertySet::PropertyReference allProperty = m_propertySet.propertyAt(m_allIndex);
-    for (unsigned i = 0; i < m_propertySet.propertyCount(); ++i) {
-        StylePropertySet::PropertyReference property = m_propertySet.propertyAt(i);
+    StylePropertySet::PropertyReference allProperty = m_propertySet->propertyAt(m_allIndex);
+    for (unsigned i = 0; i < m_propertySet->propertyCount(); ++i) {
+        StylePropertySet::PropertyReference property = m_propertySet->propertyAt(i);
         if (CSSProperty::isAffectedByAllProperty(property.id())) {
             if (allProperty.isImportant() && !property.isImportant())
                 continue;
@@ -64,27 +64,32 @@ StylePropertySerializer::StylePropertySetForSerializer::StylePropertySetForSeria
     }
 }
 
+DEFINE_TRACE(StylePropertySerializer::StylePropertySetForSerializer)
+{
+    visitor->trace(m_propertySet);
+}
+
 unsigned StylePropertySerializer::StylePropertySetForSerializer::propertyCount() const
 {
     if (!hasExpandedAllProperty())
-        return m_propertySet.propertyCount();
+        return m_propertySet->propertyCount();
     return lastCSSProperty - firstCSSProperty + 1;
 }
 
 StylePropertySerializer::PropertyValueForSerializer StylePropertySerializer::StylePropertySetForSerializer::propertyAt(unsigned index) const
 {
     if (!hasExpandedAllProperty())
-        return StylePropertySerializer::PropertyValueForSerializer(m_propertySet.propertyAt(index));
+        return StylePropertySerializer::PropertyValueForSerializer(m_propertySet->propertyAt(index));
 
     CSSPropertyID propertyID = static_cast<CSSPropertyID>(index + firstCSSProperty);
     ASSERT(firstCSSProperty <= propertyID && propertyID <= lastCSSProperty);
     if (m_longhandPropertyUsed.get(index)) {
-        int index = m_propertySet.findPropertyIndex(propertyID);
+        int index = m_propertySet->findPropertyIndex(propertyID);
         ASSERT(index != -1);
-        return StylePropertySerializer::PropertyValueForSerializer(m_propertySet.propertyAt(index));
+        return StylePropertySerializer::PropertyValueForSerializer(m_propertySet->propertyAt(index));
     }
 
-    StylePropertySet::PropertyReference property = m_propertySet.propertyAt(m_allIndex);
+    StylePropertySet::PropertyReference property = m_propertySet->propertyAt(m_allIndex);
     return StylePropertySerializer::PropertyValueForSerializer(propertyID, property.value(), property.isImportant());
 }
 
@@ -97,7 +102,7 @@ bool StylePropertySerializer::StylePropertySetForSerializer::shouldProcessProper
     // If all is not expanded, we need to process "all" and properties which
     // are not overwritten by "all".
     if (!m_needToExpandAll) {
-        StylePropertySet::PropertyReference property = m_propertySet.propertyAt(index);
+        StylePropertySet::PropertyReference property = m_propertySet->propertyAt(index);
         if (property.id() == CSSPropertyAll || !CSSProperty::isAffectedByAllProperty(property.id()))
             return true;
         return m_longhandPropertyUsed.get(property.id() - firstCSSProperty);
@@ -124,7 +129,7 @@ bool StylePropertySerializer::StylePropertySetForSerializer::shouldProcessProper
 int StylePropertySerializer::StylePropertySetForSerializer::findPropertyIndex(CSSPropertyID propertyID) const
 {
     if (!hasExpandedAllProperty())
-        return m_propertySet.findPropertyIndex(propertyID);
+        return m_propertySet->findPropertyIndex(propertyID);
     return propertyID - firstCSSProperty;
 }
 
@@ -140,7 +145,7 @@ const CSSValue* StylePropertySerializer::StylePropertySetForSerializer::getPrope
 String StylePropertySerializer::StylePropertySetForSerializer::getPropertyValue(CSSPropertyID propertyID) const
 {
     if (!hasExpandedAllProperty())
-        return m_propertySet.getPropertyValue(propertyID);
+        return m_propertySet->getPropertyValue(propertyID);
 
     const CSSValue* value = getPropertyCSSValue(propertyID);
     if (!value)