diff --git a/xpinstall/public/nsISoftwareUpdate.h b/xpinstall/public/nsISoftwareUpdate.h
index 14973a3049fe..e571b5b3ae96 100644
--- a/xpinstall/public/nsISoftwareUpdate.h
+++ b/xpinstall/public/nsISoftwareUpdate.h
@@ -86,34 +86,5 @@ class nsISoftwareUpdate : public nsISupports
 };
 
 
-/**
- * Request that an autoreg be performed at next startup. (Used
- * internally by XPI.)  This basically drops a files next to the
- * application.  Next time XPCOM sees this file, it will cause
- * an autoreg, then delete this file.
- */
-void
-NS_SoftwareUpdateRequestAutoReg()
-{
-  nsresult rv;
-  nsCOMPtr<nsIFile> file;
-  NS_GetSpecialDirectory(NS_XPCOM_CURRENT_PROCESS_DIR,
-                         getter_AddRefs(file));
-  
-  if (!file) {
-    NS_WARNING("Getting NS_XPCOM_CURRENT_PROCESS_DIR failed");
-    return;
-  }
-  
-  file->AppendNative(nsDependentCString(".autoreg"));
-  
-  rv = file->Create(nsIFile::NORMAL_FILE_TYPE, 0666);
-  
-  if (NS_FAILED(rv)) {
-    NS_WARNING("creating file failed");
-    return;
-  }
-}
-
 #endif // nsISoftwareUpdate_h__
 
diff --git a/xpinstall/src/nsInstall.cpp b/xpinstall/src/nsInstall.cpp
index e08fee92eabf..d56e74fd92e5 100644
--- a/xpinstall/src/nsInstall.cpp
+++ b/xpinstall/src/nsInstall.cpp
@@ -100,6 +100,37 @@ static NS_DEFINE_IID(kIStringBundleServiceIID, NS_ISTRINGBUNDLESERVICE_IID);
 
 #define kInstallLocaleProperties "chrome://global/locale/commonDialogs.properties"
 
+/**
+ * Request that an autoreg be performed at next startup. (Used
+ * internally by XPI.)  This basically drops a files next to the
+ * application.  Next time XPCOM sees this file, it will cause
+ * an autoreg, then delete this file.
+ */
+static void
+NS_SoftwareUpdateRequestAutoReg()
+{
+  nsresult rv;
+  nsCOMPtr<nsIFile> file;
+  NS_GetSpecialDirectory(NS_XPCOM_CURRENT_PROCESS_DIR,
+                         getter_AddRefs(file));
+  
+  if (!file) {
+    NS_WARNING("Getting NS_XPCOM_CURRENT_PROCESS_DIR failed");
+    return;
+  }
+  
+  file->AppendNative(nsDependentCString(".autoreg"));
+  
+  rv = file->Create(nsIFile::NORMAL_FILE_TYPE, 0666);
+  
+  if (NS_FAILED(rv)) {
+    NS_WARNING("creating file failed");
+    return;
+  }
+}
+
+
+
 MOZ_DECL_CTOR_COUNTER(nsInstallInfo)
 
 nsInstallInfo::nsInstallInfo(PRUint32           aInstallType,