--- a/dom/base/nsDOMClassInfo.cpp
+++ b/dom/base/nsDOMClassInfo.cpp
@@ -134,16 +134,17 @@
 
 // CSS related includes
 #include "nsCSSRules.h"
 #include "nsIDOMStyleSheet.h"
 #include "nsIDOMStyleSheetList.h"
 #include "nsIDOMCSSRule.h"
 #include "nsICSSRuleList.h"
 #include "nsIDOMRect.h"
+#include "nsIDOMCSSValueList.h"
 #include "nsDOMCSSAttrDeclaration.h"
 
 // XBL related includes.
 #include "nsXBLService.h"
 #include "nsXBLBinding.h"
 #include "nsBindingManager.h"
 #include "nsIFrame.h"
 #include "nsIPresShell.h"
@@ -979,16 +980,18 @@ static nsDOMClassInfoData sClassInfoData
   NS_DEFINE_CLASSINFO_DATA(CSSGroupRuleRuleList, nsCSSRuleListSH,
                            ARRAY_SCRIPTABLE_FLAGS)
   NS_DEFINE_CLASSINFO_DATA(MediaList, nsMediaListSH,
                            ARRAY_SCRIPTABLE_FLAGS)
   NS_DEFINE_CLASSINFO_DATA(StyleSheetList, nsStyleSheetListSH,
                            ARRAY_SCRIPTABLE_FLAGS)
   NS_DEFINE_CLASSINFO_DATA(CSSStyleSheet, nsDOMGenericSH,
                            DOM_DEFAULT_SCRIPTABLE_FLAGS)
+  NS_DEFINE_CLASSINFO_DATA(CSSValueList, nsDOMGenericSH,
+                           DOM_DEFAULT_SCRIPTABLE_FLAGS)
 
   // Range classes
   NS_DEFINE_CLASSINFO_DATA(Range, nsDOMGenericSH,
                            DOM_DEFAULT_SCRIPTABLE_FLAGS)
   NS_DEFINE_CLASSINFO_DATA(Selection, nsDOMGenericSH,
                            DEFAULT_SCRIPTABLE_FLAGS)
 
   // XUL classes
@@ -2846,16 +2849,19 @@ nsDOMClassInfo::Init()
   DOM_CLASSINFO_MAP_BEGIN(StyleSheetList, nsIDOMStyleSheetList)
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMStyleSheetList)
   DOM_CLASSINFO_MAP_END
 
   DOM_CLASSINFO_MAP_BEGIN(CSSStyleSheet, nsIDOMCSSStyleSheet)
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMCSSStyleSheet)
   DOM_CLASSINFO_MAP_END
 
+  DOM_CLASSINFO_MAP_BEGIN(CSSValueList, nsIDOMCSSValueList)
+    DOM_CLASSINFO_MAP_ENTRY(nsIDOMCSSValueList)
+  DOM_CLASSINFO_MAP_END
 
   DOM_CLASSINFO_MAP_BEGIN_NO_CLASS_IF(CSSRect, nsIDOMRect)
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMRect)
   DOM_CLASSINFO_MAP_END
 
   DOM_CLASSINFO_MAP_BEGIN(Range, nsIDOMRange)
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMRange)
   DOM_CLASSINFO_MAP_END

--- a/dom/base/nsDOMClassInfoClasses.h
+++ b/dom/base/nsDOMClassInfoClasses.h
@@ -122,16 +122,20 @@ DOMCI_CLASS(CSSImportRule)
 DOMCI_CLASS(CSSMediaRule)
 DOMCI_CLASS(CSSNameSpaceRule)
 DOMCI_CLASS(CSSRuleList)
 DOMCI_CLASS(CSSGroupRuleRuleList)
 DOMCI_CLASS(MediaList)
 DOMCI_CLASS(StyleSheetList)
 DOMCI_CLASS(CSSStyleSheet)
 
+// CSSValueList object that represents an nsIDOMCSSValueList, used
+// by DOM CSS
+DOMCI_CLASS(CSSValueList)
+
 // Range classes
 DOMCI_CLASS(Range)
 DOMCI_CLASS(Selection)
 
 // XUL classes
 #ifdef MOZ_XUL
 DOMCI_CLASS(XULDocument)
 DOMCI_CLASS(XULElement)

--- a/dom/bindings/Bindings.conf
+++ b/dom/bindings/Bindings.conf
@@ -180,16 +180,17 @@ DOMInterfaces = {
 },
 
 "CSSValue": {
   "concrete": False
 },
 
 "CSSValueList": {
   "nativeType": "nsDOMCSSValueList",
+  "hasInstanceInterface": "nsIDOMCSSValueList"
 },
 
 'DelayNode': [
 {
     'resultNotAddRefed': [ 'delayTime' ],
 }],
 
 'Document': [

--- a/dom/interfaces/css/Makefile.in
+++ b/dom/interfaces/css/Makefile.in
@@ -16,16 +16,17 @@ GRE_MODULE	= 1
 
 SDK_XPIDLSRCS = 				\
 	nsIDOMCSSPrimitiveValue.idl		\
 	nsIDOMCSSRule.idl			\
 	nsIDOMCSSRuleList.idl			\
 	nsIDOMCSSStyleDeclaration.idl		\
 	nsIDOMCSSStyleSheet.idl			\
 	nsIDOMCSSValue.idl			\
+	nsIDOMCSSValueList.idl			\
 	nsIDOMElementCSSInlineStyle.idl		\
 	$(NULL)
 
 XPIDLSRCS =					\
 	nsIDOMCSSCharsetRule.idl		\
 	nsIDOMCSSConditionRule.idl		\
 	nsIDOMCSSFontFaceRule.idl		\
 	nsIDOMCSSGroupingRule.idl		\

new file mode 100644
--- /dev/null
+++ b/dom/interfaces/css/nsIDOMCSSValueList.idl
@@ -0,0 +1,12 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "domstubs.idl"
+#include "nsIDOMCSSValue.idl"
+
+[scriptable, uuid(92364ed1-e364-4175-bc52-c2fe9671cbc7)]
+interface nsIDOMCSSValueList : nsIDOMCSSValue
+{
+};

--- a/dom/tests/mochitest/chrome/Makefile.in
+++ b/dom/tests/mochitest/chrome/Makefile.in
@@ -46,16 +46,17 @@ MOCHITEST_CHROME_FILES = \
 		test_sandbox_postMessage.html \
 		test_sandbox_bindings.xul \
 		test_selectAtPoint.html \
 		selectAtPoint.html \
 		test_bug799299.xul \
 		file_bug799299.xul \
 		test_bug800817.xul \
 		file_bug800817.xul \
+		test_bug830396.xul \
 		test_subscript_bindings.xul \
 		file_subscript_bindings.js \
 		test_sandbox_eventhandler.xul \
 		test_DOM_element_instanceof.xul \
 		file_DOM_element_instanceof.xul \
 		$(NULL)
 
 ifeq (WINNT,$(OS_ARCH))

new file mode 100644
--- /dev/null
+++ b/dom/tests/mochitest/chrome/test_bug830396.xul
@@ -0,0 +1,41 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=830396
+-->
+<window title="Mozilla Bug 830396"
+  xmlns:html="http://www.w3.org/1999/xhtml"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <title>Test for Bug 830396</title>
+  <script type="application/javascript"
+          src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+function runTests()
+{
+  var doc = frames[0].document;
+  var cs = doc.defaultView.getComputedStyle(doc.body);
+  var nsIDOMCSSValueList = Components.interfaces.nsIDOMCSSValueList;
+  ok(cs.getPropertyCSSValue("cursor") instanceof nsIDOMCSSValueList,
+     "CSSValueList should be a nsIDOMCSSValueList");
+  SimpleTest.finish();
+}
+]]>
+</script>
+<body onload="runTests();"  xmlns="http://www.w3.org/1999/xhtml">
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=830396">Mozilla Bug 830396</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+</pre>
+<iframe type="content"></iframe>
+</body>
+
+
+</window>

--- a/layout/style/nsDOMCSSValueList.cpp
+++ b/layout/style/nsDOMCSSValueList.cpp
@@ -4,37 +4,42 @@
 
 /* DOM object representing lists of values in DOM computed style */
 
 #include "nsDOMCSSValueList.h"
 #include "nsCOMPtr.h"
 #include "mozilla/dom/CSSValueListBinding.h"
 #include "nsError.h"
 #include "nsContentUtils.h"
+#include "nsDOMClassInfoID.h"
 
 using namespace mozilla;
 
 nsDOMCSSValueList::nsDOMCSSValueList(bool aCommaDelimited, bool aReadonly)
   : CSSValue(), mCommaDelimited(aCommaDelimited), mReadonly(aReadonly)
 {
   SetIsDOMBinding();
 }
 
 nsDOMCSSValueList::~nsDOMCSSValueList()
 {
 }
 
 NS_IMPL_CYCLE_COLLECTING_ADDREF(nsDOMCSSValueList)
 NS_IMPL_CYCLE_COLLECTING_RELEASE(nsDOMCSSValueList)
 
+  DOMCI_DATA(CSSValueList, nsDOMCSSValueList)
+
 // QueryInterface implementation for nsDOMCSSValueList
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsDOMCSSValueList)
   NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
   NS_INTERFACE_MAP_ENTRY(nsIDOMCSSValue)
+  NS_INTERFACE_MAP_ENTRY(nsIDOMCSSValueList)
   NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, CSSValue)
+  NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO(CSSValueList)
 NS_INTERFACE_MAP_END
 
 NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_1(nsDOMCSSValueList, mCSSValues)
 
 JSObject*
 nsDOMCSSValueList::WrapObject(JSContext *cx, JSObject *scope, bool *tried)
 {
   return dom::CSSValueListBinding::Wrap(cx, scope, this, tried);

--- a/layout/style/nsDOMCSSValueList.h
+++ b/layout/style/nsDOMCSSValueList.h
@@ -2,25 +2,25 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 /* DOM object representing lists of values in DOM computed style */
 
 #ifndef nsDOMCSSValueList_h___
 #define nsDOMCSSValueList_h___
 
-#include "nsIDOMCSSValue.h"
+#include "nsIDOMCSSValueList.h"
 #include "CSSValue.h"
 #include "nsAutoPtr.h"
 #include "nsTArray.h"
 
 class nsComputedDOMStyle;
 
 class nsDOMCSSValueList MOZ_FINAL : public mozilla::dom::CSSValue,
-  public nsIDOMCSSValue
+  public nsIDOMCSSValueList
 {
 public:
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_AMBIGUOUS(nsDOMCSSValueList, mozilla::dom::CSSValue)
 
   // nsIDOMCSSValue
   NS_DECL_NSIDOMCSSVALUE