diff --git a/mozilla/content/html/style/src/nsComputedDOMStyle.cpp b/mozilla/content/html/style/src/nsComputedDOMStyle.cpp
index c4708d402ed..0558bb23a2b 100644
--- a/mozilla/content/html/style/src/nsComputedDOMStyle.cpp
+++ b/mozilla/content/html/style/src/nsComputedDOMStyle.cpp
@@ -95,7 +95,7 @@ NS_NewComputedDOMStyle(nsIComputedDOMStyle** aComputedStyle)
 }
 
 nsComputedDOMStyle::nsComputedDOMStyle()
-  : mInner(nsnull), mPresShellWeak(nsnull), mT2P(0.0f)
+  : mInner(this), mPresShellWeak(nsnull), mT2P(0.0f)
 {
 }
 
@@ -116,55 +116,15 @@ nsComputedDOMStyle::Shutdown()
 }
 
 
-NS_IMETHODIMP
-nsComputedDOMStyle::QueryInterface(REFNSIID aIID, void** aInstancePtr)
-{
-  if (!aInstancePtr) {
-    NS_ERROR("QueryInterface requires a non-NULL destination!");
-    return NS_ERROR_NULL_POINTER;
-  }
-
-  nsISupports* inst;
-
-  if (aIID.Equals(NS_GET_IID(nsIComputedDOMStyle))) {
-    inst = NS_STATIC_CAST(nsIComputedDOMStyle*, this);
-  } else if (aIID.Equals(NS_GET_IID(nsIDOMCSSStyleDeclaration))) {
-    inst = NS_STATIC_CAST(nsIDOMCSSStyleDeclaration*, this);
-  } else if (aIID.Equals(NS_GET_IID(nsIDOMCSS2Properties))) {
-    if (!mInner) {
-      mInner = new CSS2PropertiesTearoff(this);
-      NS_ENSURE_TRUE(mInner, NS_ERROR_OUT_OF_MEMORY);
-    }
-    inst = NS_STATIC_CAST(nsIDOMCSS2Properties*,
-                          NS_STATIC_CAST(nsISupports*, mInner));
-  } else if (aIID.Equals(NS_GET_IID(nsIDOMNSCSS2Properties))) {
-    if (!mInner) {
-      mInner = new CSS2PropertiesTearoff(this);
-      NS_ENSURE_TRUE(mInner, NS_ERROR_OUT_OF_MEMORY);
-    }
-    inst = NS_STATIC_CAST(nsIDOMNSCSS2Properties*,
-                          NS_STATIC_CAST(nsISupports*, mInner));
-  } else if (aIID.Equals(NS_GET_IID(nsISupports))) {
-    inst = NS_STATIC_CAST(nsISupports*,
-                          NS_STATIC_CAST(nsIComputedDOMStyle*, this));
-  } else if (aIID.Equals(NS_GET_IID(nsIClassInfo))) {
-    inst = nsContentUtils::GetClassInfoInstance(eDOMClassInfo_ComputedCSSStyleDeclaration_id);
-    NS_ENSURE_TRUE(inst, NS_ERROR_OUT_OF_MEMORY);
-  } else {
-    inst = nsnull;
-  }
-
-  nsresult rv;
-  if (!inst) {
-    rv = NS_NOINTERFACE;
-  } else {
-    NS_ADDREF(inst);
-    rv = NS_OK;
-  }
-
-  *aInstancePtr = inst;
-  return rv;
-}
+// QueryInterface implementation for nsComputedDOMStyle
+NS_INTERFACE_MAP_BEGIN(nsComputedDOMStyle)
+  NS_INTERFACE_MAP_ENTRY(nsIComputedDOMStyle)
+  NS_INTERFACE_MAP_ENTRY(nsIDOMCSSStyleDeclaration)
+  NS_INTERFACE_MAP_ENTRY_AGGREGATED(nsIDOMCSS2Properties, &mInner)
+  NS_INTERFACE_MAP_ENTRY_AGGREGATED(nsIDOMNSCSS2Properties, &mInner)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIComputedDOMStyle)
+  NS_INTERFACE_MAP_ENTRY_CONTENT_CLASSINFO(ComputedCSSStyleDeclaration)
+NS_INTERFACE_MAP_END
 
 
 static void doDestroyComputedDOMStyle(nsComputedDOMStyle *aComputedStyle)
diff --git a/mozilla/content/html/style/src/nsComputedDOMStyle.h b/mozilla/content/html/style/src/nsComputedDOMStyle.h
index 09dede074b1..51318bc05e0 100644
--- a/mozilla/content/html/style/src/nsComputedDOMStyle.h
+++ b/mozilla/content/html/style/src/nsComputedDOMStyle.h
@@ -292,7 +292,7 @@ private:
 
   static const ComputedStyleMapEntry* GetQueryablePropertyMap(PRUint32* aLength);
 
-  nsCOMPtr<nsISupports> mInner; // CSS2Properties
+  CSS2PropertiesTearoff mInner;
 
   nsWeakPtr mPresShellWeak;
   nsCOMPtr<nsIContent> mContent;
diff --git a/mozilla/content/html/style/src/nsDOMCSSDeclaration.cpp b/mozilla/content/html/style/src/nsDOMCSSDeclaration.cpp
index 850ef087d57..a2332b6e3b1 100644
--- a/mozilla/content/html/style/src/nsDOMCSSDeclaration.cpp
+++ b/mozilla/content/html/style/src/nsDOMCSSDeclaration.cpp
@@ -50,7 +50,7 @@
 
 
 nsDOMCSSDeclaration::nsDOMCSSDeclaration()
-  : mInner(nsnull)
+  : mInner(this)
 {
 }
 
@@ -59,54 +59,14 @@ nsDOMCSSDeclaration::~nsDOMCSSDeclaration()
 }
 
 
-NS_IMETHODIMP
-nsDOMCSSDeclaration::QueryInterface(REFNSIID aIID, void** aInstancePtr)
-{
-  if (!aInstancePtr) {
-    NS_ERROR("QueryInterface requires a non-NULL destination!");
-    return NS_ERROR_NULL_POINTER;
-  }
-
-  nsISupports* inst;
-
-  if (aIID.Equals(NS_GET_IID(nsIDOMCSSStyleDeclaration))) {
-    inst = NS_STATIC_CAST(nsIDOMCSSStyleDeclaration*, this);
-  } else if (aIID.Equals(NS_GET_IID(nsIDOMCSS2Properties))) {
-    if (!mInner) {
-      mInner = new CSS2PropertiesTearoff(this);
-      NS_ENSURE_TRUE(mInner, NS_ERROR_OUT_OF_MEMORY);
-    }
-    inst = NS_STATIC_CAST(nsIDOMCSS2Properties*,
-                          NS_STATIC_CAST(nsISupports*, mInner));
-  } else if (aIID.Equals(NS_GET_IID(nsIDOMNSCSS2Properties))) {
-    if (!mInner) {
-      mInner = new CSS2PropertiesTearoff(this);
-      NS_ENSURE_TRUE(mInner, NS_ERROR_OUT_OF_MEMORY);
-    }
-    inst = NS_STATIC_CAST(nsIDOMNSCSS2Properties*,
-                          NS_STATIC_CAST(nsISupports*, mInner));
-  } else if (aIID.Equals(NS_GET_IID(nsISupports))) {
-    inst = NS_STATIC_CAST(nsISupports*,
-                          NS_STATIC_CAST(nsIDOMCSSStyleDeclaration*, this));
-  } else if (aIID.Equals(NS_GET_IID(nsIClassInfo))) {
-    inst = nsContentUtils::GetClassInfoInstance(eDOMClassInfo_CSSStyleDeclaration_id);
-    NS_ENSURE_TRUE(inst, NS_ERROR_OUT_OF_MEMORY);
-  } else {
-    inst = nsnull;
-  }
-
-  nsresult rv;
-  if (!inst) {
-    rv = NS_NOINTERFACE;
-  } else {
-    NS_ADDREF(inst);
-    rv = NS_OK;
-  }
-
-  *aInstancePtr = inst;
-  return rv;
-}
-
+// QueryInterface implementation for nsDOMCSSDeclaration
+NS_INTERFACE_MAP_BEGIN(nsDOMCSSDeclaration)
+  NS_INTERFACE_MAP_ENTRY(nsIDOMCSSStyleDeclaration)
+  NS_INTERFACE_MAP_ENTRY_AGGREGATED(nsIDOMCSS2Properties, &mInner)
+  NS_INTERFACE_MAP_ENTRY_AGGREGATED(nsIDOMNSCSS2Properties, &mInner)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIDOMCSSStyleDeclaration)
+  NS_INTERFACE_MAP_ENTRY_CONTENT_CLASSINFO(CSSStyleDeclaration)
+NS_INTERFACE_MAP_END
 
 NS_IMPL_ADDREF(nsDOMCSSDeclaration);
 NS_IMPL_RELEASE(nsDOMCSSDeclaration);
@@ -338,22 +298,33 @@ nsDOMCSSDeclaration::ParseDeclaration(const nsAString& aDecl,
 
 //////////////////////////////////////////////////////////////////////////////
 
-CSS2PropertiesTearoff::CSS2PropertiesTearoff(nsISupports *aOuter)
+CSS2PropertiesTearoff::CSS2PropertiesTearoff(nsIDOMCSSStyleDeclaration *aOuter)
+  : mOuter(aOuter)
 {
-  NS_INIT_AGGREGATED(aOuter);
+  NS_ASSERTION(mOuter, "must have outer");
 }
 
 CSS2PropertiesTearoff::~CSS2PropertiesTearoff()
 {
 }
 
-NS_IMPL_AGGREGATED(CSS2PropertiesTearoff);
+NS_IMETHODIMP_(nsrefcnt)
+CSS2PropertiesTearoff::AddRef(void)
+{
+  return mOuter->AddRef();
+}
 
-NS_INTERFACE_MAP_BEGIN_AGGREGATED(CSS2PropertiesTearoff)
-  NS_INTERFACE_MAP_ENTRY(nsIDOMCSS2Properties)
-  NS_INTERFACE_MAP_ENTRY(nsIDOMNSCSS2Properties)
-NS_INTERFACE_MAP_END_AGGREGATED(fOuter)
+NS_IMETHODIMP_(nsrefcnt)
+CSS2PropertiesTearoff::Release(void)
+{
+  return mOuter->Release();
+}
 
+NS_IMETHODIMP
+CSS2PropertiesTearoff::QueryInterface(REFNSIID aIID, void** aInstancePtr)
+{
+  return mOuter->QueryInterface(aIID, aInstancePtr);
+}
 
 // nsIDOMCSS2Properties
 // nsIDOMNSCSS2Properties
@@ -362,16 +333,14 @@ NS_INTERFACE_MAP_END_AGGREGATED(fOuter)
   NS_IMETHODIMP                                                         \
   CSS2PropertiesTearoff::Get##method_(nsAString& aValue)                \
   {                                                                     \
-    return NS_STATIC_CAST(nsIDOMCSSStyleDeclaration*, fOuter)->         \
-      GetPropertyValue(NS_LITERAL_STRING(#name_), aValue);              \
+    return mOuter->GetPropertyValue(NS_LITERAL_STRING(#name_), aValue); \
   }                                                                     \
                                                                         \
   NS_IMETHODIMP                                                         \
   CSS2PropertiesTearoff::Set##method_(const nsAString& aValue)          \
   {                                                                     \
-    return NS_STATIC_CAST(nsIDOMCSSStyleDeclaration*, fOuter)->         \
-      SetProperty(NS_LITERAL_STRING(#name_), aValue,                    \
-                  NS_LITERAL_STRING(""));                               \
+    return mOuter->SetProperty(NS_LITERAL_STRING(#name_), aValue,       \
+                               NS_LITERAL_STRING(""));                  \
   }
 
 #define CSS_PROP_LIST_EXCLUDE_INTERNAL
diff --git a/mozilla/content/html/style/src/nsDOMCSSDeclaration.h b/mozilla/content/html/style/src/nsDOMCSSDeclaration.h
index b24fbdcebff..680810a87a4 100644
--- a/mozilla/content/html/style/src/nsDOMCSSDeclaration.h
+++ b/mozilla/content/html/style/src/nsDOMCSSDeclaration.h
@@ -38,18 +38,29 @@
 #ifndef nsDOMCSSDeclaration_h___
 #define nsDOMCSSSDeclaration_h___
 
-#include "nsISupports.h"
 #include "nsIDOMCSSStyleDeclaration.h"
 #include "nsIDOMCSS2Properties.h"
 
-#include "nsAgg.h"
-#include "nsCOMPtr.h"
-
 class nsCSSDeclaration;
 class nsICSSParser;
 class nsICSSLoader;
 class nsIURI;
 
+class CSS2PropertiesTearoff : public nsIDOMNSCSS2Properties
+{
+public:
+  NS_DECL_ISUPPORTS_INHERITED
+
+  NS_DECL_NSIDOMCSS2PROPERTIES
+  NS_DECL_NSIDOMNSCSS2PROPERTIES
+
+  CSS2PropertiesTearoff(nsIDOMCSSStyleDeclaration *aOuter);
+  virtual ~CSS2PropertiesTearoff();
+
+private:
+  nsIDOMCSSStyleDeclaration* mOuter;
+};
+
 class nsDOMCSSDeclaration : public nsIDOMCSSStyleDeclaration
 {
 public:
@@ -99,21 +110,7 @@ protected:
   virtual ~nsDOMCSSDeclaration();
 
 private:
-  nsCOMPtr<nsISupports> mInner; // CSS2Properties
+  CSS2PropertiesTearoff mInner;
 };
 
-
-class CSS2PropertiesTearoff : public nsIDOMNSCSS2Properties
-{
-public:
-  NS_DECL_AGGREGATED
-
-  NS_DECL_NSIDOMCSS2PROPERTIES
-  NS_DECL_NSIDOMNSCSS2PROPERTIES
-
-  CSS2PropertiesTearoff(nsISupports *aOuter);
-  virtual ~CSS2PropertiesTearoff();
-};
-
-
 #endif // nsDOMCSSDeclaration_h___
diff --git a/mozilla/layout/style/nsComputedDOMStyle.cpp b/mozilla/layout/style/nsComputedDOMStyle.cpp
index c4708d402ed..0558bb23a2b 100644
--- a/mozilla/layout/style/nsComputedDOMStyle.cpp
+++ b/mozilla/layout/style/nsComputedDOMStyle.cpp
@@ -95,7 +95,7 @@ NS_NewComputedDOMStyle(nsIComputedDOMStyle** aComputedStyle)
 }
 
 nsComputedDOMStyle::nsComputedDOMStyle()
-  : mInner(nsnull), mPresShellWeak(nsnull), mT2P(0.0f)
+  : mInner(this), mPresShellWeak(nsnull), mT2P(0.0f)
 {
 }
 
@@ -116,55 +116,15 @@ nsComputedDOMStyle::Shutdown()
 }
 
 
-NS_IMETHODIMP
-nsComputedDOMStyle::QueryInterface(REFNSIID aIID, void** aInstancePtr)
-{
-  if (!aInstancePtr) {
-    NS_ERROR("QueryInterface requires a non-NULL destination!");
-    return NS_ERROR_NULL_POINTER;
-  }
-
-  nsISupports* inst;
-
-  if (aIID.Equals(NS_GET_IID(nsIComputedDOMStyle))) {
-    inst = NS_STATIC_CAST(nsIComputedDOMStyle*, this);
-  } else if (aIID.Equals(NS_GET_IID(nsIDOMCSSStyleDeclaration))) {
-    inst = NS_STATIC_CAST(nsIDOMCSSStyleDeclaration*, this);
-  } else if (aIID.Equals(NS_GET_IID(nsIDOMCSS2Properties))) {
-    if (!mInner) {
-      mInner = new CSS2PropertiesTearoff(this);
-      NS_ENSURE_TRUE(mInner, NS_ERROR_OUT_OF_MEMORY);
-    }
-    inst = NS_STATIC_CAST(nsIDOMCSS2Properties*,
-                          NS_STATIC_CAST(nsISupports*, mInner));
-  } else if (aIID.Equals(NS_GET_IID(nsIDOMNSCSS2Properties))) {
-    if (!mInner) {
-      mInner = new CSS2PropertiesTearoff(this);
-      NS_ENSURE_TRUE(mInner, NS_ERROR_OUT_OF_MEMORY);
-    }
-    inst = NS_STATIC_CAST(nsIDOMNSCSS2Properties*,
-                          NS_STATIC_CAST(nsISupports*, mInner));
-  } else if (aIID.Equals(NS_GET_IID(nsISupports))) {
-    inst = NS_STATIC_CAST(nsISupports*,
-                          NS_STATIC_CAST(nsIComputedDOMStyle*, this));
-  } else if (aIID.Equals(NS_GET_IID(nsIClassInfo))) {
-    inst = nsContentUtils::GetClassInfoInstance(eDOMClassInfo_ComputedCSSStyleDeclaration_id);
-    NS_ENSURE_TRUE(inst, NS_ERROR_OUT_OF_MEMORY);
-  } else {
-    inst = nsnull;
-  }
-
-  nsresult rv;
-  if (!inst) {
-    rv = NS_NOINTERFACE;
-  } else {
-    NS_ADDREF(inst);
-    rv = NS_OK;
-  }
-
-  *aInstancePtr = inst;
-  return rv;
-}
+// QueryInterface implementation for nsComputedDOMStyle
+NS_INTERFACE_MAP_BEGIN(nsComputedDOMStyle)
+  NS_INTERFACE_MAP_ENTRY(nsIComputedDOMStyle)
+  NS_INTERFACE_MAP_ENTRY(nsIDOMCSSStyleDeclaration)
+  NS_INTERFACE_MAP_ENTRY_AGGREGATED(nsIDOMCSS2Properties, &mInner)
+  NS_INTERFACE_MAP_ENTRY_AGGREGATED(nsIDOMNSCSS2Properties, &mInner)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIComputedDOMStyle)
+  NS_INTERFACE_MAP_ENTRY_CONTENT_CLASSINFO(ComputedCSSStyleDeclaration)
+NS_INTERFACE_MAP_END
 
 
 static void doDestroyComputedDOMStyle(nsComputedDOMStyle *aComputedStyle)
diff --git a/mozilla/layout/style/nsComputedDOMStyle.h b/mozilla/layout/style/nsComputedDOMStyle.h
index 09dede074b1..51318bc05e0 100644
--- a/mozilla/layout/style/nsComputedDOMStyle.h
+++ b/mozilla/layout/style/nsComputedDOMStyle.h
@@ -292,7 +292,7 @@ private:
 
   static const ComputedStyleMapEntry* GetQueryablePropertyMap(PRUint32* aLength);
 
-  nsCOMPtr<nsISupports> mInner; // CSS2Properties
+  CSS2PropertiesTearoff mInner;
 
   nsWeakPtr mPresShellWeak;
   nsCOMPtr<nsIContent> mContent;
diff --git a/mozilla/layout/style/nsDOMCSSDeclaration.cpp b/mozilla/layout/style/nsDOMCSSDeclaration.cpp
index 850ef087d57..a2332b6e3b1 100644
--- a/mozilla/layout/style/nsDOMCSSDeclaration.cpp
+++ b/mozilla/layout/style/nsDOMCSSDeclaration.cpp
@@ -50,7 +50,7 @@
 
 
 nsDOMCSSDeclaration::nsDOMCSSDeclaration()
-  : mInner(nsnull)
+  : mInner(this)
 {
 }
 
@@ -59,54 +59,14 @@ nsDOMCSSDeclaration::~nsDOMCSSDeclaration()
 }
 
 
-NS_IMETHODIMP
-nsDOMCSSDeclaration::QueryInterface(REFNSIID aIID, void** aInstancePtr)
-{
-  if (!aInstancePtr) {
-    NS_ERROR("QueryInterface requires a non-NULL destination!");
-    return NS_ERROR_NULL_POINTER;
-  }
-
-  nsISupports* inst;
-
-  if (aIID.Equals(NS_GET_IID(nsIDOMCSSStyleDeclaration))) {
-    inst = NS_STATIC_CAST(nsIDOMCSSStyleDeclaration*, this);
-  } else if (aIID.Equals(NS_GET_IID(nsIDOMCSS2Properties))) {
-    if (!mInner) {
-      mInner = new CSS2PropertiesTearoff(this);
-      NS_ENSURE_TRUE(mInner, NS_ERROR_OUT_OF_MEMORY);
-    }
-    inst = NS_STATIC_CAST(nsIDOMCSS2Properties*,
-                          NS_STATIC_CAST(nsISupports*, mInner));
-  } else if (aIID.Equals(NS_GET_IID(nsIDOMNSCSS2Properties))) {
-    if (!mInner) {
-      mInner = new CSS2PropertiesTearoff(this);
-      NS_ENSURE_TRUE(mInner, NS_ERROR_OUT_OF_MEMORY);
-    }
-    inst = NS_STATIC_CAST(nsIDOMNSCSS2Properties*,
-                          NS_STATIC_CAST(nsISupports*, mInner));
-  } else if (aIID.Equals(NS_GET_IID(nsISupports))) {
-    inst = NS_STATIC_CAST(nsISupports*,
-                          NS_STATIC_CAST(nsIDOMCSSStyleDeclaration*, this));
-  } else if (aIID.Equals(NS_GET_IID(nsIClassInfo))) {
-    inst = nsContentUtils::GetClassInfoInstance(eDOMClassInfo_CSSStyleDeclaration_id);
-    NS_ENSURE_TRUE(inst, NS_ERROR_OUT_OF_MEMORY);
-  } else {
-    inst = nsnull;
-  }
-
-  nsresult rv;
-  if (!inst) {
-    rv = NS_NOINTERFACE;
-  } else {
-    NS_ADDREF(inst);
-    rv = NS_OK;
-  }
-
-  *aInstancePtr = inst;
-  return rv;
-}
-
+// QueryInterface implementation for nsDOMCSSDeclaration
+NS_INTERFACE_MAP_BEGIN(nsDOMCSSDeclaration)
+  NS_INTERFACE_MAP_ENTRY(nsIDOMCSSStyleDeclaration)
+  NS_INTERFACE_MAP_ENTRY_AGGREGATED(nsIDOMCSS2Properties, &mInner)
+  NS_INTERFACE_MAP_ENTRY_AGGREGATED(nsIDOMNSCSS2Properties, &mInner)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIDOMCSSStyleDeclaration)
+  NS_INTERFACE_MAP_ENTRY_CONTENT_CLASSINFO(CSSStyleDeclaration)
+NS_INTERFACE_MAP_END
 
 NS_IMPL_ADDREF(nsDOMCSSDeclaration);
 NS_IMPL_RELEASE(nsDOMCSSDeclaration);
@@ -338,22 +298,33 @@ nsDOMCSSDeclaration::ParseDeclaration(const nsAString& aDecl,
 
 //////////////////////////////////////////////////////////////////////////////
 
-CSS2PropertiesTearoff::CSS2PropertiesTearoff(nsISupports *aOuter)
+CSS2PropertiesTearoff::CSS2PropertiesTearoff(nsIDOMCSSStyleDeclaration *aOuter)
+  : mOuter(aOuter)
 {
-  NS_INIT_AGGREGATED(aOuter);
+  NS_ASSERTION(mOuter, "must have outer");
 }
 
 CSS2PropertiesTearoff::~CSS2PropertiesTearoff()
 {
 }
 
-NS_IMPL_AGGREGATED(CSS2PropertiesTearoff);
+NS_IMETHODIMP_(nsrefcnt)
+CSS2PropertiesTearoff::AddRef(void)
+{
+  return mOuter->AddRef();
+}
 
-NS_INTERFACE_MAP_BEGIN_AGGREGATED(CSS2PropertiesTearoff)
-  NS_INTERFACE_MAP_ENTRY(nsIDOMCSS2Properties)
-  NS_INTERFACE_MAP_ENTRY(nsIDOMNSCSS2Properties)
-NS_INTERFACE_MAP_END_AGGREGATED(fOuter)
+NS_IMETHODIMP_(nsrefcnt)
+CSS2PropertiesTearoff::Release(void)
+{
+  return mOuter->Release();
+}
 
+NS_IMETHODIMP
+CSS2PropertiesTearoff::QueryInterface(REFNSIID aIID, void** aInstancePtr)
+{
+  return mOuter->QueryInterface(aIID, aInstancePtr);
+}
 
 // nsIDOMCSS2Properties
 // nsIDOMNSCSS2Properties
@@ -362,16 +333,14 @@ NS_INTERFACE_MAP_END_AGGREGATED(fOuter)
   NS_IMETHODIMP                                                         \
   CSS2PropertiesTearoff::Get##method_(nsAString& aValue)                \
   {                                                                     \
-    return NS_STATIC_CAST(nsIDOMCSSStyleDeclaration*, fOuter)->         \
-      GetPropertyValue(NS_LITERAL_STRING(#name_), aValue);              \
+    return mOuter->GetPropertyValue(NS_LITERAL_STRING(#name_), aValue); \
   }                                                                     \
                                                                         \
   NS_IMETHODIMP                                                         \
   CSS2PropertiesTearoff::Set##method_(const nsAString& aValue)          \
   {                                                                     \
-    return NS_STATIC_CAST(nsIDOMCSSStyleDeclaration*, fOuter)->         \
-      SetProperty(NS_LITERAL_STRING(#name_), aValue,                    \
-                  NS_LITERAL_STRING(""));                               \
+    return mOuter->SetProperty(NS_LITERAL_STRING(#name_), aValue,       \
+                               NS_LITERAL_STRING(""));                  \
   }
 
 #define CSS_PROP_LIST_EXCLUDE_INTERNAL
diff --git a/mozilla/layout/style/nsDOMCSSDeclaration.h b/mozilla/layout/style/nsDOMCSSDeclaration.h
index b24fbdcebff..680810a87a4 100644
--- a/mozilla/layout/style/nsDOMCSSDeclaration.h
+++ b/mozilla/layout/style/nsDOMCSSDeclaration.h
@@ -38,18 +38,29 @@
 #ifndef nsDOMCSSDeclaration_h___
 #define nsDOMCSSSDeclaration_h___
 
-#include "nsISupports.h"
 #include "nsIDOMCSSStyleDeclaration.h"
 #include "nsIDOMCSS2Properties.h"
 
-#include "nsAgg.h"
-#include "nsCOMPtr.h"
-
 class nsCSSDeclaration;
 class nsICSSParser;
 class nsICSSLoader;
 class nsIURI;
 
+class CSS2PropertiesTearoff : public nsIDOMNSCSS2Properties
+{
+public:
+  NS_DECL_ISUPPORTS_INHERITED
+
+  NS_DECL_NSIDOMCSS2PROPERTIES
+  NS_DECL_NSIDOMNSCSS2PROPERTIES
+
+  CSS2PropertiesTearoff(nsIDOMCSSStyleDeclaration *aOuter);
+  virtual ~CSS2PropertiesTearoff();
+
+private:
+  nsIDOMCSSStyleDeclaration* mOuter;
+};
+
 class nsDOMCSSDeclaration : public nsIDOMCSSStyleDeclaration
 {
 public:
@@ -99,21 +110,7 @@ protected:
   virtual ~nsDOMCSSDeclaration();
 
 private:
-  nsCOMPtr<nsISupports> mInner; // CSS2Properties
+  CSS2PropertiesTearoff mInner;
 };
 
-
-class CSS2PropertiesTearoff : public nsIDOMNSCSS2Properties
-{
-public:
-  NS_DECL_AGGREGATED
-
-  NS_DECL_NSIDOMCSS2PROPERTIES
-  NS_DECL_NSIDOMNSCSS2PROPERTIES
-
-  CSS2PropertiesTearoff(nsISupports *aOuter);
-  virtual ~CSS2PropertiesTearoff();
-};
-
-
 #endif // nsDOMCSSDeclaration_h___