diff --git a/dom/bindings/Bindings.conf b/dom/bindings/Bindings.conf
index af8c45ba3cc8..c55a7e38dfac 100644
--- a/dom/bindings/Bindings.conf
+++ b/dom/bindings/Bindings.conf
@@ -213,6 +213,11 @@ DOMInterfaces = {
     'concrete': False
 },
 
+'ChromeWindow': {
+    'concrete': False,
+    'register': False,
+},
+
 'ChromeWorker': {
     'headerFile': 'mozilla/dom/WorkerPrivate.h',
     'nativeType': 'mozilla::dom::workers::ChromeWorkerPrivate',
@@ -1494,6 +1499,8 @@ DOMInterfaces = {
 
 'Window': {
     'nativeType': 'nsGlobalWindow',
+    # When turning on Window, remember to drop the "'register': False"
+    # from ChromeWindow.
     'hasXPConnectImpls': True,
     'register': False,
     'implicitJSContext': [ 'setInterval', 'setTimeout' ],
diff --git a/dom/bindings/Codegen.py b/dom/bindings/Codegen.py
index cc78315dd535..a52fb7d8c19f 100644
--- a/dom/bindings/Codegen.py
+++ b/dom/bindings/Codegen.py
@@ -1286,15 +1286,19 @@ class CGClassHasInstanceHook(CGAbstractStaticMethod):
     return true;
   }
   """
+        if self.descriptor.interface.identifier.name == "ChromeWindow":
+            setBp = "*bp = UnwrapDOMObject<nsGlobalWindow>(js::UncheckedUnwrap(instance))->IsChromeWindow()"
+        else:
+            setBp = "*bp = true"
         # Sort interaces implementing self by name so we get stable output.
         for iface in sorted(self.descriptor.interface.interfacesImplementingSelf,
                             key=lambda iface: iface.identifier.name):
             hasInstanceCode += """
   if (domClass->mInterfaceChain[PrototypeTraits<prototypes::id::%s>::Depth] == prototypes::id::%s) {
-    *bp = true;
+    %s;
     return true;
   }
-""" % (iface.identifier.name, iface.identifier.name)
+""" % (iface.identifier.name, iface.identifier.name, setBp)
         hasInstanceCode += "  return true;"
         return header + hasInstanceCode;
 
diff --git a/dom/webidl/Window.webidl b/dom/webidl/Window.webidl
index 1b8409897f7f..8f0b436161d4 100644
--- a/dom/webidl/Window.webidl
+++ b/dom/webidl/Window.webidl
@@ -339,3 +339,7 @@ partial interface Window {
 Window implements TouchEventHandlers;
 
 Window implements OnErrorEventHandlerForWindow;
+
+[ChromeOnly] interface ChromeWindow {};
+
+Window implements ChromeWindow;