diff --git a/dom/base/nsDOMClassInfo.cpp b/dom/base/nsDOMClassInfo.cpp
index 1d62908fbff..e2ba752a2cf 100644
--- a/dom/base/nsDOMClassInfo.cpp
+++ b/dom/base/nsDOMClassInfo.cpp
@@ -908,8 +908,6 @@ static nsDOMClassInfoData sClassInfoData[] = {
                            DOM_DEFAULT_SCRIPTABLE_FLAGS)
   NS_DEFINE_CLASSINFO_DATA(CSSStyleDeclaration, nsCSSStyleDeclSH,
                            ARRAY_SCRIPTABLE_FLAGS)
-  NS_DEFINE_CLASSINFO_DATA(ComputedCSSStyleDeclaration, nsCSSStyleDeclSH,
-                           ARRAY_SCRIPTABLE_FLAGS)
   NS_DEFINE_CLASSINFO_DATA(ROCSSPrimitiveValue, nsDOMGenericSH,
                            DOM_DEFAULT_SCRIPTABLE_FLAGS)
 
@@ -3004,12 +3002,6 @@ nsDOMClassInfo::Init()
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMCSS2Properties)
   DOM_CLASSINFO_MAP_END
 
-  DOM_CLASSINFO_MAP_BEGIN_NO_CLASS_IF(ComputedCSSStyleDeclaration,
-                                      nsIDOMCSSStyleDeclaration)
-    DOM_CLASSINFO_MAP_ENTRY(nsIDOMCSSStyleDeclaration)
-    DOM_CLASSINFO_MAP_ENTRY(nsIDOMCSS2Properties)
-  DOM_CLASSINFO_MAP_END
-
   DOM_CLASSINFO_MAP_BEGIN_NO_CLASS_IF(ROCSSPrimitiveValue,
                                       nsIDOMCSSPrimitiveValue)
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMCSSPrimitiveValue)
diff --git a/dom/base/nsDOMClassInfoClasses.h b/dom/base/nsDOMClassInfoClasses.h
index f667289ee2b..21d07d1c06f 100644
--- a/dom/base/nsDOMClassInfoClasses.h
+++ b/dom/base/nsDOMClassInfoClasses.h
@@ -156,7 +156,6 @@ DOMCI_CLASS(MediaList)
 DOMCI_CLASS(StyleSheetList)
 DOMCI_CLASS(CSSStyleSheet)
 DOMCI_CLASS(CSSStyleDeclaration)
-DOMCI_CLASS(ComputedCSSStyleDeclaration)
 DOMCI_CLASS(ROCSSPrimitiveValue)
 
 // Range classes
diff --git a/layout/style/nsComputedDOMStyle.cpp b/layout/style/nsComputedDOMStyle.cpp
index c3568b8ed03..b86b4977e61 100644
--- a/layout/style/nsComputedDOMStyle.cpp
+++ b/layout/style/nsComputedDOMStyle.cpp
@@ -161,19 +161,11 @@ nsComputedDOMStyle::Shutdown()
 
 NS_IMPL_CYCLE_COLLECTION_1(nsComputedDOMStyle, mContent)
 
-DOMCI_DATA(ComputedCSSStyleDeclaration, nsComputedDOMStyle)
-
 // QueryInterface implementation for nsComputedDOMStyle
-NS_INTERFACE_TABLE_HEAD(nsComputedDOMStyle)
-  NS_INTERFACE_TABLE3(nsComputedDOMStyle,
-                      nsICSSDeclaration,
-                      nsIDOMCSSStyleDeclaration,
-                      nsIDOMCSS2Properties)
-  NS_INTERFACE_TABLE_TO_MAP_SEGUE
+NS_INTERFACE_MAP_BEGIN(nsComputedDOMStyle)
   NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
   NS_INTERFACE_MAP_ENTRIES_CYCLE_COLLECTION(nsComputedDOMStyle)
-  NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO(ComputedCSSStyleDeclaration)
-NS_INTERFACE_MAP_END
+NS_INTERFACE_MAP_END_INHERITING(nsDOMCSSDeclaration)
 
 
 static void doDestroyComputedDOMStyle(nsComputedDOMStyle *aComputedStyle)