diff --git a/mozilla/caps/src/nsPrincipal.cpp b/mozilla/caps/src/nsPrincipal.cpp
index f04dcb7e713..60953fb6a40 100755
--- a/mozilla/caps/src/nsPrincipal.cpp
+++ b/mozilla/caps/src/nsPrincipal.cpp
@@ -140,8 +140,18 @@ nsPrincipal::GetOrigin(char **aOrigin)
   NS_ASSERTION(uri, "No Domain or Codebase");
 
   nsCAutoString hostPort;
-  nsresult rv = uri->GetHostPort(hostPort);
-  if (NS_SUCCEEDED(rv)) {
+
+  // chrome: URLs don't have a meaningful origin, so make
+  // sure we just get the full spec for them.
+  // XXX this should be removed in favor of the solution in
+  // bug 160042.
+  PRBool isChrome;
+  nsresult rv = uri->SchemeIs("chrome", &isChrome);
+  if (NS_SUCCEEDED(rv) && !isChrome) {
+    rv = uri->GetHostPort(hostPort);
+  }
+
+  if (NS_SUCCEEDED(rv) && !isChrome) {
     nsCAutoString scheme;
     rv = uri->GetScheme(scheme);
     NS_ENSURE_SUCCESS(rv, rv);
diff --git a/mozilla/caps/src/nsScriptSecurityManager.cpp b/mozilla/caps/src/nsScriptSecurityManager.cpp
index 8b03ae45ed8..1fbaefc2e8f 100644
--- a/mozilla/caps/src/nsScriptSecurityManager.cpp
+++ b/mozilla/caps/src/nsScriptSecurityManager.cpp
@@ -1654,25 +1654,28 @@ nsScriptSecurityManager::GetCodebasePrincipal(nsIURI *aURI,
     rv = CreateCodebasePrincipal(aURI, getter_AddRefs(principal));
     if (NS_FAILED(rv)) return rv;
 
-    //-- Check to see if we already have this principal.
-    nsCOMPtr<nsIPrincipal> fromTable;
-    mPrincipals.Get(principal, getter_AddRefs(fromTable));
-    if (fromTable)
-        principal = fromTable;
-    else //-- Check to see if we have a more general principal
+    if (mPrincipals.Count() > 0)
     {
-        nsXPIDLCString originUrl;
-        rv = principal->GetOrigin(getter_Copies(originUrl));
-        if (NS_FAILED(rv)) return rv;
-        nsCOMPtr<nsIURI> newURI;
-        rv = NS_NewURI(getter_AddRefs(newURI), originUrl, nsnull, sIOService);
-        if (NS_FAILED(rv)) return rv;
-        nsCOMPtr<nsIPrincipal> principal2;
-        rv = CreateCodebasePrincipal(newURI, getter_AddRefs(principal2));
-        if (NS_FAILED(rv)) return rv;
-        mPrincipals.Get(principal2, getter_AddRefs(fromTable));
+        //-- Check to see if we already have this principal.
+        nsCOMPtr<nsIPrincipal> fromTable;
+        mPrincipals.Get(principal, getter_AddRefs(fromTable));
         if (fromTable)
             principal = fromTable;
+        else //-- Check to see if we have a more general principal
+        {
+            nsXPIDLCString originUrl;
+            rv = principal->GetOrigin(getter_Copies(originUrl));
+            if (NS_FAILED(rv)) return rv;
+            nsCOMPtr<nsIURI> newURI;
+            rv = NS_NewURI(getter_AddRefs(newURI), originUrl, nsnull, sIOService);
+            if (NS_FAILED(rv)) return rv;
+            nsCOMPtr<nsIPrincipal> principal2;
+            rv = CreateCodebasePrincipal(newURI, getter_AddRefs(principal2));
+            if (NS_FAILED(rv)) return rv;
+            mPrincipals.Get(principal2, getter_AddRefs(fromTable));
+            if (fromTable)
+                principal = fromTable;
+        }
     }
 
     NS_IF_ADDREF(*result = principal);