diff --git a/content/base/public/nsIDOMFile.idl b/content/base/public/nsIDOMFile.idl
index f317562ae75..f0048d10f9b 100644
--- a/content/base/public/nsIDOMFile.idl
+++ b/content/base/public/nsIDOMFile.idl
@@ -82,7 +82,7 @@ interface nsIDOMFile : nsIDOMBlob
 };
 
 [scriptable, uuid(c4a77171-039b-4f84-97f9-820fb51626af)]
-interface nsIDOMBlobBuilder : nsISupports
+interface nsIDOMMozBlobBuilder : nsISupports
 {
   nsIDOMBlob getBlob([optional] in DOMString contentType);
   [implicit_jscontext] void append(in jsval data);
diff --git a/content/base/src/nsDOMBlobBuilder.cpp b/content/base/src/nsDOMBlobBuilder.cpp
index 3aad463f982..482f345ca93 100644
--- a/content/base/src/nsDOMBlobBuilder.cpp
+++ b/content/base/src/nsDOMBlobBuilder.cpp
@@ -221,7 +221,7 @@ nsDOMMultipartBlob::MozSlice(PRInt64 aStart, PRInt64 aEnd,
   return NS_OK;
 }
 
-class nsDOMBlobBuilder : public nsIDOMBlobBuilder
+class nsDOMBlobBuilder : public nsIDOMMozBlobBuilder
 {
 public:
   nsDOMBlobBuilder()
@@ -229,7 +229,7 @@ public:
   {}
 
   NS_DECL_ISUPPORTS
-  NS_DECL_NSIDOMBLOBBUILDER
+  NS_DECL_NSIDOMMOZBLOBBUILDER
 protected:
   nsresult AppendVoidPtr(void* aData, PRUint32 aLength);
   nsresult AppendString(JSString* aString, JSContext* aCx);
@@ -287,7 +287,7 @@ DOMCI_DATA(MozBlobBuilder, nsDOMBlobBuilder)
 NS_IMPL_ADDREF(nsDOMBlobBuilder)
 NS_IMPL_RELEASE(nsDOMBlobBuilder)
 NS_INTERFACE_MAP_BEGIN(nsDOMBlobBuilder)
-  NS_INTERFACE_MAP_ENTRY(nsIDOMBlobBuilder)
+  NS_INTERFACE_MAP_ENTRY(nsIDOMMozBlobBuilder)
   NS_INTERFACE_MAP_ENTRY(nsISupports)
   NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO(MozBlobBuilder)
 NS_INTERFACE_MAP_END
diff --git a/dom/base/nsDOMClassInfo.cpp b/dom/base/nsDOMClassInfo.cpp
index 9b50677d2a4..fad93daa418 100644
--- a/dom/base/nsDOMClassInfo.cpp
+++ b/dom/base/nsDOMClassInfo.cpp
@@ -4037,8 +4037,8 @@ nsDOMClassInfo::Init()
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMMozURLProperty)
   DOM_CLASSINFO_MAP_END
 
-  DOM_CLASSINFO_MAP_BEGIN(MozBlobBuilder, nsIDOMBlobBuilder)
-    DOM_CLASSINFO_MAP_ENTRY(nsIDOMBlobBuilder)
+  DOM_CLASSINFO_MAP_BEGIN(MozBlobBuilder, nsIDOMMozBlobBuilder)
+    DOM_CLASSINFO_MAP_ENTRY(nsIDOMMozBlobBuilder)
   DOM_CLASSINFO_MAP_END
 
   DOM_CLASSINFO_MAP_BEGIN(DOMStringMap, nsIDOMDOMStringMap)