Support for CSSOM CSSNamespaceRule interface

Source/core/css/StyleSheetContents.h

Index: Source/core/css/StyleSheetContents.h
diff --git a/Source/core/css/StyleSheetContents.h b/Source/core/css/StyleSheetContents.h
index aad72df37d3abc5978baffbdcff3301c66bc7104..eaa97d6f10070e1b78dcd78cc0c61eaa76bbc84d 100644
--- a/Source/core/css/StyleSheetContents.h
+++ b/Source/core/css/StyleSheetContents.h
@@ -44,6 +44,7 @@ class SecurityOrigin;
 class StyleRuleBase;
 class StyleRuleFontFace;
 class StyleRuleImport;
+class StyleRuleNamespace;
 
 class CORE_EXPORT StyleSheetContents : public RefCountedWillBeGarbageCollectedFinalized<StyleSheetContents> {
 public:
@@ -102,6 +103,7 @@ public:
     // Rules other than @import.
     const WillBeHeapVector<RefPtrWillBeMember<StyleRuleBase>>& childRules() const { return m_childRules; }
     const WillBeHeapVector<RefPtrWillBeMember<StyleRuleImport>>& importRules() const { return m_importRules; }
+    const WillBeHeapVector<RefPtrWillBeMember<StyleRuleNamespace>>& namespaceRules() const { return m_namespaceRules; }
 
     void notifyLoadedSheet(const CSSStyleSheetResource*);
 
@@ -171,6 +173,7 @@ private:
     String m_originalURL;
 
     WillBeHeapVector<RefPtrWillBeMember<StyleRuleImport>> m_importRules;
+    WillBeHeapVector<RefPtrWillBeMember<StyleRuleNamespace>> m_namespaceRules;
     WillBeHeapVector<RefPtrWillBeMember<StyleRuleBase>> m_childRules;
     typedef HashMap<AtomicString, AtomicString> PrefixNamespaceURIMap;
     PrefixNamespaceURIMap m_namespaces;