diff --git a/caps/idl/nsIScriptSecurityManager.idl b/caps/idl/nsIScriptSecurityManager.idl
index 7dfa1ab7f535..63c224d0e5be 100644
--- a/caps/idl/nsIScriptSecurityManager.idl
+++ b/caps/idl/nsIScriptSecurityManager.idl
@@ -11,7 +11,7 @@ interface nsIChannel;
 interface nsIDocShell;
 interface nsIDomainPolicy;
 
-[scriptable, uuid(2911ae60-1b5f-47e6-941e-1bb7b53a167d)]
+[scriptable, uuid(712aa338-50a1-497b-be6f-dc3d97867c01)]
 interface nsIScriptSecurityManager : nsIXPCSecurityManager
 {
     ///////////////// Security Checks //////////////////
@@ -160,12 +160,10 @@ interface nsIScriptSecurityManager : nsIXPCSecurityManager
      */
     [deprecated] nsIPrincipal getCodebasePrincipal(in nsIURI uri);
 
-    ///////////////////////
     /**
      * Return the principal of the specified object in the specified context.
      */
-    [noscript] nsIPrincipal getObjectPrincipal(in JSContextPtr cx,
-                                               in JSObjectPtr obj);
+    [implicit_jscontext] nsIPrincipal getObjectPrincipal(in jsval aObject);
 
     /**
      * Returns true if the principal of the currently running script is the
diff --git a/caps/src/nsScriptSecurityManager.cpp b/caps/src/nsScriptSecurityManager.cpp
index 1898bd182136..d196273dfd62 100644
--- a/caps/src/nsScriptSecurityManager.cpp
+++ b/caps/src/nsScriptSecurityManager.cpp
@@ -1487,14 +1487,14 @@ nsScriptSecurityManager::GetSubjectPrincipal(JSContext *cx,
 }
 
 NS_IMETHODIMP
-nsScriptSecurityManager::GetObjectPrincipal(JSContext *aCx, JSObject *aObj,
+nsScriptSecurityManager::GetObjectPrincipal(const JS::Value &aObjectVal,
+                                            JSContext *aCx,
                                             nsIPrincipal **result)
 {
-    JS::Rooted<JSObject*> obj(aCx, aObj);
-    *result = doGetObjectPrincipal(obj);
-    if (!*result)
-        return NS_ERROR_FAILURE;
-    NS_ADDREF(*result);
+    NS_ENSURE_TRUE(aObjectVal.isObject(), NS_ERROR_FAILURE);
+    JS::RootedObject obj(aCx, &aObjectVal.toObject());
+    nsCOMPtr<nsIPrincipal> principal = doGetObjectPrincipal(obj);
+    principal.forget(result);
     return NS_OK;
 }
 
diff --git a/js/xpconnect/loader/mozJSSubScriptLoader.cpp b/js/xpconnect/loader/mozJSSubScriptLoader.cpp
index ce348e78750e..67e2305a94ae 100644
--- a/js/xpconnect/loader/mozJSSubScriptLoader.cpp
+++ b/js/xpconnect/loader/mozJSSubScriptLoader.cpp
@@ -258,15 +258,8 @@ mozJSSubScriptLoader::DoLoadSubScriptWithOptions(const nsAString& url,
     if (!targetObj)
         return NS_ERROR_FAILURE;
 
-    if (targetObj != result_obj) {
-        nsCOMPtr<nsIScriptSecurityManager> secman =
-            do_GetService(NS_SCRIPTSECURITYMANAGER_CONTRACTID);
-        if (!secman)
-            return NS_ERROR_FAILURE;
-
-        rv = secman->GetObjectPrincipal(cx, targetObj, getter_AddRefs(principal));
-        NS_ENSURE_SUCCESS(rv, rv);
-    }
+    if (targetObj != result_obj)
+        principal = GetObjectPrincipal(targetObj);
 
     JSAutoCompartment ac(cx, targetObj);
 
diff --git a/js/xpconnect/src/XPCWrappedJSClass.cpp b/js/xpconnect/src/XPCWrappedJSClass.cpp
index a4af49e708a8..58bd93ea6b9d 100644
--- a/js/xpconnect/src/XPCWrappedJSClass.cpp
+++ b/js/xpconnect/src/XPCWrappedJSClass.cpp
@@ -652,14 +652,9 @@ nsXPCWrappedJSClass::DelegatedQueryInterface(nsXPCWrappedJS* self,
             return NS_NOINTERFACE;
 
         RootedObject selfObj(ccx, self->GetJSObject());
-        nsCOMPtr<nsIPrincipal> objPrin;
-        nsresult rv = secMan->GetObjectPrincipal(ccx, selfObj,
-                                                 getter_AddRefs(objPrin));
-        if (NS_FAILED(rv))
-            return rv;
-
+        nsCOMPtr<nsIPrincipal> objPrin = GetObjectPrincipal(selfObj);
         bool isSystem;
-        rv = secMan->IsSystemPrincipal(objPrin, &isSystem);
+        nsresult rv = secMan->IsSystemPrincipal(objPrin, &isSystem);
         if ((NS_FAILED(rv) || !isSystem) && !IS_WN_REFLECTOR(selfObj)) {
             // A content object.
             nsRefPtr<SameOriginCheckedComponent> checked =
diff --git a/js/xpconnect/tests/unit/test_getObjectPrincipal.js b/js/xpconnect/tests/unit/test_getObjectPrincipal.js
new file mode 100644
index 000000000000..e2f3c88ba5f3
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_getObjectPrincipal.js
@@ -0,0 +1,4 @@
+function run_test() {
+  var secMan = Cc["@mozilla.org/scriptsecuritymanager;1"].getService(Ci.nsIScriptSecurityManager);
+  do_check_true(secMan.isSystemPrincipal(secMan.getObjectPrincipal({})));
+}
diff --git a/js/xpconnect/tests/unit/xpcshell.ini b/js/xpconnect/tests/unit/xpcshell.ini
index a39d909a384c..378a73887299 100644
--- a/js/xpconnect/tests/unit/xpcshell.ini
+++ b/js/xpconnect/tests/unit/xpcshell.ini
@@ -73,6 +73,7 @@ fail-if = os == "android"
 [test_sandbox_atob.js]
 [test_isProxy.js]
 [test_watchdog_enable.js]
+[test_getObjectPrincipal.js]
 head = head_watchdog.js
 [test_watchdog_disable.js]
 head = head_watchdog.js