--- a/js/xpconnect/src/XPCJSRuntime.cpp
+++ b/js/xpconnect/src/XPCJSRuntime.cpp
@@ -77,16 +77,20 @@ const char* const XPCJSRuntime::mStrings
     "constructor",          // IDX_CONSTRUCTOR
     "toString",             // IDX_TO_STRING
     "toSource",             // IDX_TO_SOURCE
     "lastResult",           // IDX_LAST_RESULT
     "returnCode",           // IDX_RETURN_CODE
     "value",                // IDX_VALUE
     "QueryInterface",       // IDX_QUERY_INTERFACE
     "Components",           // IDX_COMPONENTS
+    "Cc",                   // IDX_CC
+    "Ci",                   // IDX_CI
+    "Cr",                   // IDX_CR
+    "Cu",                   // IDX_CU
     "wrappedJSObject",      // IDX_WRAPPED_JSOBJECT
     "Object",               // IDX_OBJECT
     "Function",             // IDX_FUNCTION
     "prototype",            // IDX_PROTOTYPE
     "createInstance",       // IDX_CREATE_INSTANCE
     "item",                 // IDX_ITEM
     "__proto__",            // IDX_PROTO
     "eval",                 // IDX_EVAL

--- a/js/xpconnect/src/XPCWrappedNativeScope.cpp
+++ b/js/xpconnect/src/XPCWrappedNativeScope.cpp
@@ -219,16 +219,34 @@ XPCWrappedNativeScope::GetComponentsJSOb
 void
 XPCWrappedNativeScope::ForcePrivilegedComponents()
 {
     nsCOMPtr<nsIXPCComponents> c = do_QueryInterface(mComponents);
     if (!c)
         mComponents = new nsXPCComponents(this);
 }
 
+static bool
+DefineSubcomponentProperty(JSContext* aCx,
+                           HandleObject aGlobal,
+                           nsISupports* aSubcomponent,
+                           const nsID* aIID,
+                           unsigned int aStringIndex)
+{
+    RootedValue subcompVal(aCx);
+    xpcObjectHelper helper(aSubcomponent);
+    if (!XPCConvert::NativeInterface2JSObject(&subcompVal, helper,
+                                              aIID, false, nullptr))
+        return false;
+    if (NS_WARN_IF(!subcompVal.isObject()))
+        return false;
+    RootedId id(aCx, XPCJSContext::Get()->GetStringID(aStringIndex));
+    return JS_DefinePropertyById(aCx, aGlobal, id, subcompVal, 0);
+}
+
 bool
 XPCWrappedNativeScope::AttachComponentsObject(JSContext* aCx)
 {
     RootedObject components(aCx);
     if (!GetComponentsJSObject(&components))
         return false;
 
     RootedObject global(aCx, GetGlobalJSObject());
@@ -238,17 +256,40 @@ XPCWrappedNativeScope::AttachComponentsO
     // nsXPCComponents object. That way, if it's an nsXPCComponentsBase,
     // enableUniversalXPConnect can upgrade it later.
     unsigned attrs = JSPROP_READONLY | JSPROP_RESOLVING;
     nsCOMPtr<nsIXPCComponents> c = do_QueryInterface(mComponents);
     if (c)
         attrs |= JSPROP_PERMANENT;
 
     RootedId id(aCx, XPCJSContext::Get()->GetStringID(XPCJSContext::IDX_COMPONENTS));
-    return JS_DefinePropertyById(aCx, global, id, components, attrs);
+    if (!JS_DefinePropertyById(aCx, global, id, components, attrs))
+        return false;
+
+// _iid can be nullptr if the object implements classinfo.
+#define DEFINE_SUBCOMPONENT_PROPERTY(_comp, _type, _iid, _id)                     \
+    nsCOMPtr<nsIXPCComponents_ ## _type> obj ## _type;                            \
+    if (NS_FAILED(_comp->Get ## _type(getter_AddRefs( obj ## _type ))))           \
+        return false;                                                             \
+    if (!DefineSubcomponentProperty(aCx, global, obj ## _type, _iid,              \
+                                    XPCJSContext::IDX_ ## _id))                   \
+        return false;
+
+    DEFINE_SUBCOMPONENT_PROPERTY(mComponents, Interfaces, nullptr, CI)
+    DEFINE_SUBCOMPONENT_PROPERTY(mComponents, Results, nullptr, CR)
+
+    if (!c)
+        return true;
+
+    DEFINE_SUBCOMPONENT_PROPERTY(c, Classes, nullptr, CC)
+    DEFINE_SUBCOMPONENT_PROPERTY(c, Utils, &NS_GET_IID(nsIXPCComponents_Utils), CU)
+
+#undef DEFINE_SUBCOMPONENT_PROPERTY
+
+    return true;
 }
 
 static bool
 CompartmentPerAddon()
 {
     static bool initialized = false;
     static bool pref = false;
 

--- a/js/xpconnect/src/xpcprivate.h
+++ b/js/xpconnect/src/xpcprivate.h
@@ -430,16 +430,20 @@ public:
         IDX_CONSTRUCTOR             = 0 ,
         IDX_TO_STRING               ,
         IDX_TO_SOURCE               ,
         IDX_LAST_RESULT             ,
         IDX_RETURN_CODE             ,
         IDX_VALUE                   ,
         IDX_QUERY_INTERFACE         ,
         IDX_COMPONENTS              ,
+        IDX_CC                      ,
+        IDX_CI                      ,
+        IDX_CR                      ,
+        IDX_CU                      ,
         IDX_WRAPPED_JSOBJECT        ,
         IDX_OBJECT                  ,
         IDX_FUNCTION                ,
         IDX_PROTOTYPE               ,
         IDX_CREATE_INSTANCE         ,
         IDX_ITEM                    ,
         IDX_PROTO                   ,
         IDX_EVAL                    ,

--- a/testing/talos/talos/scripts/MozillaFileLogger.js
+++ b/testing/talos/talos/scripts/MozillaFileLogger.js
@@ -29,21 +29,16 @@ function contentAsyncEvent(type, data) {
 function dumpLog(msg) {
   dump(msg);
   MozFileLogger.log(msg);
 }
 
 
 netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
 
-if (Cc === undefined) {
-  var Cc = Components.classes;
-  var Ci = Components.interfaces;
-}
-
 const FOSTREAM_CID = "@mozilla.org/network/file-output-stream;1";
 const LF_CID = "@mozilla.org/file/local;1";
 
 // File status flags. It is a bitwise OR of the following bit flags.
 // Only one of the first three flags below may be used.
 const PR_READ_ONLY    = 0x01; // Open for reading only.
 const PR_WRITE_ONLY   = 0x02; // Open for writing only.
 const PR_READ_WRITE   = 0x04; // Open for reading and writing.