diff --git a/layout/style/nsCSSStruct.h b/layout/style/nsCSSStruct.h
index 5bb8cf007b00..2bc04aace220 100644
--- a/layout/style/nsCSSStruct.h
+++ b/layout/style/nsCSSStruct.h
@@ -104,15 +104,7 @@ struct nsCSSStruct {
 };
 
 // We use the nsCSS* structures for storing css::Declaration's
-// *temporary* data during parsing and modification.  (They are too big
-// for permanent storage.)  We also use them for nsRuleData, with some
-// additions of things that the style system must cascade, but that
-// aren't CSS properties.  Thus we use typedefs and inheritance
-// (forwards, when the rule data needs extra data) to make the rule data
-// structs from the declaration structs.
-// NOTE:  For compilation speed, this typedef also appears in nsRuleNode.h
-typedef nsCSSStruct nsRuleDataStruct;
-
+// *temporary* data during parsing and modification.
 
 struct nsCSSFont : public nsCSSStruct {
   nsCSSFont(void);
@@ -139,12 +131,6 @@ private:
   nsCSSFont(const nsCSSFont& aOther); // NOT IMPLEMENTED
 };
 
-struct nsRuleDataFont : public nsCSSFont {
-  nsRuleDataFont() {}
-private:
-  nsRuleDataFont(const nsRuleDataFont& aOther); // NOT IMPLEMENTED
-};
-
 struct nsCSSColor : public nsCSSStruct  {
   nsCSSColor(void);
   ~nsCSSColor(void);
@@ -163,12 +149,6 @@ private:
   nsCSSColor(const nsCSSColor& aOther); // NOT IMPLEMENTED
 };
 
-struct nsRuleDataColor : public nsCSSColor {
-  nsRuleDataColor() {}
-private:
-  nsRuleDataColor(const nsRuleDataColor& aOther); // NOT IMPLEMENTED
-};
-
 struct nsCSSText : public nsCSSStruct  {
   nsCSSText(void);
   ~nsCSSText(void);
@@ -190,12 +170,6 @@ private:
   nsCSSText(const nsCSSText& aOther); // NOT IMPLEMENTED
 };
 
-struct nsRuleDataText : public nsCSSText {
-  nsRuleDataText() {}
-private:
-  nsRuleDataText(const nsRuleDataText& aOther); // NOT IMPLEMENTED
-};
-
 struct nsCSSDisplay : public nsCSSStruct  {
   nsCSSDisplay(void);
   ~nsCSSDisplay(void);
@@ -229,13 +203,6 @@ private:
   nsCSSDisplay(const nsCSSDisplay& aOther); // NOT IMPLEMENTED
 };
 
-struct nsRuleDataDisplay : public nsCSSDisplay {
-  nsCSSValue mLang;
-  nsRuleDataDisplay() {}
-private:
-  nsRuleDataDisplay(const nsRuleDataDisplay& aOther); // NOT IMPLEMENTED
-};
-
 struct nsCSSMargin : public nsCSSStruct  {
   nsCSSMargin(void);
   ~nsCSSMargin(void);
@@ -289,12 +256,6 @@ private:
   nsCSSMargin(const nsCSSMargin& aOther); // NOT IMPLEMENTED
 };
 
-struct nsRuleDataMargin : public nsCSSMargin {
-  nsRuleDataMargin() {}
-private:
-  nsRuleDataMargin(const nsRuleDataMargin& aOther); // NOT IMPLEMENTED
-};
-
 struct nsCSSPosition : public nsCSSStruct  {
   nsCSSPosition(void);
   ~nsCSSPosition(void);
@@ -312,12 +273,6 @@ private:
   nsCSSPosition(const nsCSSPosition& aOther); // NOT IMPLEMENTED
 };
 
-struct nsRuleDataPosition : public nsCSSPosition {
-  nsRuleDataPosition() {}
-private:
-  nsRuleDataPosition(const nsRuleDataPosition& aOther); // NOT IMPLEMENTED
-};
-
 struct nsCSSList : public nsCSSStruct  {
   nsCSSList(void);
   ~nsCSSList(void);
@@ -330,12 +285,6 @@ private:
   nsCSSList(const nsCSSList& aOther); // NOT IMPLEMENTED
 };
 
-struct nsRuleDataList : public nsCSSList {
-  nsRuleDataList() {}
-private:
-  nsRuleDataList(const nsRuleDataList& aOther); // NOT IMPLEMENTED
-};
-
 struct nsCSSTable : public nsCSSStruct  { // NEW
   nsCSSTable(void);
   ~nsCSSTable(void);
@@ -350,14 +299,6 @@ private:
   nsCSSTable(const nsCSSTable& aOther); // NOT IMPLEMENTED
 };
 
-struct nsRuleDataTable : public nsCSSTable {
-  nsRuleDataTable() {}
-  nsCSSValue mSpan; // Not mappable via CSS, only using HTML4 table attrs.
-  nsCSSValue mCols; // Not mappable via CSS, only using HTML4 table attrs.
-private:
-  nsRuleDataTable(const nsRuleDataTable& aOther); // NOT IMPLEMENTED
-};
-
 struct nsCSSBreaks : public nsCSSStruct  { // NEW
   nsCSSBreaks(void);
   ~nsCSSBreaks(void);
@@ -373,12 +314,6 @@ private:
   nsCSSBreaks(const nsCSSBreaks& aOther); // NOT IMPLEMENTED
 };
 
-struct nsRuleDataBreaks : public nsCSSBreaks {
-  nsRuleDataBreaks() {}
-private:
-  nsRuleDataBreaks(const nsRuleDataBreaks& aOther); // NOT IMPLEMENTED
-};
-
 struct nsCSSPage : public nsCSSStruct  { // NEW
   nsCSSPage(void);
   ~nsCSSPage(void);
@@ -389,12 +324,6 @@ private:
   nsCSSPage(const nsCSSPage& aOther); // NOT IMPLEMENTED
 };
 
-struct nsRuleDataPage : public nsCSSPage {
-  nsRuleDataPage() {}
-private:
-  nsRuleDataPage(const nsRuleDataPage& aOther); // NOT IMPLEMENTED
-};
-
 struct nsCSSContent : public nsCSSStruct  {
   nsCSSContent(void);
   ~nsCSSContent(void);
@@ -408,12 +337,6 @@ private:
   nsCSSContent(const nsCSSContent& aOther); // NOT IMPLEMENTED
 };
 
-struct nsRuleDataContent : public nsCSSContent {
-  nsRuleDataContent() {}
-private:
-  nsRuleDataContent(const nsRuleDataContent& aOther); // NOT IMPLEMENTED
-};
-
 struct nsCSSUserInterface : public nsCSSStruct  { // NEW
   nsCSSUserInterface(void);
   ~nsCSSUserInterface(void);
@@ -431,12 +354,6 @@ private:
   nsCSSUserInterface(const nsCSSUserInterface& aOther); // NOT IMPLEMENTED
 };
 
-struct nsRuleDataUserInterface : public nsCSSUserInterface {
-  nsRuleDataUserInterface() {}
-private:
-  nsRuleDataUserInterface(const nsRuleDataUserInterface& aOther); // NOT IMPLEMENTED
-};
-
 struct nsCSSAural : public nsCSSStruct  { // NEW
   nsCSSAural(void);
   ~nsCSSAural(void);
@@ -462,12 +379,6 @@ private:
   nsCSSAural(const nsCSSAural& aOther); // NOT IMPLEMENTED
 };
 
-struct nsRuleDataAural : public nsCSSAural {
-  nsRuleDataAural() {}
-private:
-  nsRuleDataAural(const nsRuleDataAural& aOther); // NOT IMPLEMENTED
-};
-
 struct nsCSSXUL : public nsCSSStruct  {
   nsCSSXUL(void);
   ~nsCSSXUL(void);
@@ -483,12 +394,6 @@ private:
   nsCSSXUL(const nsCSSXUL& aOther); // NOT IMPLEMENTED
 };
 
-struct nsRuleDataXUL : public nsCSSXUL {
-  nsRuleDataXUL() {}
-private:
-  nsRuleDataXUL(const nsRuleDataXUL& aOther); // NOT IMPLEMENTED
-};
-
 struct nsCSSColumn : public nsCSSStruct  {
   nsCSSColumn(void);
   ~nsCSSColumn(void);
@@ -503,12 +408,6 @@ private:
   nsCSSColumn(const nsCSSColumn& aOther); // NOT IMPLEMENTED
 };
 
-struct nsRuleDataColumn : public nsCSSColumn {
-  nsRuleDataColumn() {}
-private:
-  nsRuleDataColumn(const nsRuleDataColumn& aOther); // NOT IMPLEMENTED
-};
-
 struct nsCSSSVG : public nsCSSStruct {
   nsCSSSVG(void);
   ~nsCSSSVG(void);
@@ -547,10 +446,4 @@ private:
   nsCSSSVG(const nsCSSSVG& aOther); // NOT IMPLEMENTED
 };
 
-struct nsRuleDataSVG : public nsCSSSVG {
-  nsRuleDataSVG() {}
-private:
-  nsRuleDataSVG(const nsRuleDataSVG& aOther); // NOT IMPLEMENTED
-};
-
 #endif /* nsCSSStruct_h___ */