diff --git a/dom/base/nsStyledElement.cpp b/dom/base/nsStyledElement.cpp
index 607926a484..4fd423acc7 100644
--- a/dom/base/nsStyledElement.cpp
+++ b/dom/base/nsStyledElement.cpp
@@ -25,9 +25,11 @@
 using namespace mozilla;
 using namespace mozilla::dom;
 
-NS_IMPL_QUERY_INTERFACE_INHERITED(nsStyledElement,
-                                  nsStyledElementBase,
-                                  nsStyledElement)
+// Using the CC variant of this, even though this class does not define
+// a new CC participant, to make QIing to the CC interfaces faster.
+NS_IMPL_QUERY_INTERFACE_CYCLE_COLLECTION_INHERITED(nsStyledElement,
+                                                   nsStyledElementBase,
+                                                   nsStyledElement)
 
 //----------------------------------------------------------------------
 // nsIContent methods
diff --git a/dom/base/nsTextNode.cpp b/dom/base/nsTextNode.cpp
index 3fd45f4668..b91c9e5571 100644
--- a/dom/base/nsTextNode.cpp
+++ b/dom/base/nsTextNode.cpp
@@ -97,8 +97,13 @@ nsTextNode::~nsTextNode()
 {
 }
 
-NS_IMPL_ISUPPORTS_INHERITED(nsTextNode, nsGenericDOMDataNode, nsIDOMNode,
-                            nsIDOMText, nsIDOMCharacterData)
+// Using the CC variant of this, even though this class does not define
+// a new CC participant, to make QIing to the CC interfaces faster.
+NS_IMPL_ISUPPORTS_CYCLE_COLLECTION_INHERITED(nsTextNode,
+                                             nsGenericDOMDataNode,
+                                             nsIDOMNode,
+                                             nsIDOMText,
+                                             nsIDOMCharacterData)
 
 JSObject*
 nsTextNode::WrapNode(JSContext *aCx, JS::Handle<JSObject*> aGivenProto)