diff --git a/dom/ipc/TabChild.cpp b/dom/ipc/TabChild.cpp
index 16ca6619c8e6..618635ba8183 100644
--- a/dom/ipc/TabChild.cpp
+++ b/dom/ipc/TabChild.cpp
@@ -102,9 +102,9 @@ TabChild::Init()
   return NS_OK;
 }
 
-NS_IMPL_ISUPPORTS5(TabChild, nsIWebBrowserChrome, nsIWebBrowserChrome2,
+NS_IMPL_ISUPPORTS6(TabChild, nsIWebBrowserChrome, nsIWebBrowserChrome2,
                    nsIEmbeddingSiteWindow, nsIEmbeddingSiteWindow2,
-                   nsIWebBrowserChromeFocus)
+                   nsIWebBrowserChromeFocus, nsIInterfaceRequestor)
 
 NS_IMETHODIMP
 TabChild::SetStatus(PRUint32 aStatusType, const PRUnichar* aStatus)
@@ -246,6 +246,14 @@ TabChild::FocusPrevElement()
   return NS_OK;
 }
 
+NS_IMETHODIMP
+TabChild::GetInterface(const nsIID & aIID, void **aSink)
+{
+    // XXXbz should we restrict the set of interfaces we hand out here?
+    // See bug 537429
+    return QueryInterface(aIID, aSink);
+}
+
 bool
 TabChild::RecvcreateWidget(const MagicWindowHandle& parentWidget)
 {
diff --git a/dom/ipc/TabChild.h b/dom/ipc/TabChild.h
index 632ce5f00e52..339e1f79281f 100644
--- a/dom/ipc/TabChild.h
+++ b/dom/ipc/TabChild.h
@@ -48,6 +48,7 @@
 #include "nsIWebBrowserChromeFocus.h"
 #include "nsIDOMEventListener.h"
 #include "nsIDOMEventTarget.h"
+#include "nsIInterfaceRequestor.h"
 
 namespace mozilla {
 namespace dom {
@@ -67,7 +68,8 @@ protected:
 class TabChild : public PIFrameEmbeddingChild,
                  public nsIWebBrowserChrome2,
                  public nsIEmbeddingSiteWindow2,
-                 public nsIWebBrowserChromeFocus
+                 public nsIWebBrowserChromeFocus,
+                 public nsIInterfaceRequestor
 {
 public:
     TabChild();
@@ -81,6 +83,7 @@ public:
     NS_DECL_NSIEMBEDDINGSITEWINDOW
     NS_DECL_NSIEMBEDDINGSITEWINDOW2
     NS_DECL_NSIWEBBROWSERCHROMEFOCUS
+    NS_DECL_NSIINTERFACEREQUESTOR
 
     virtual bool RecvcreateWidget(const MagicWindowHandle& parentWidget);
     virtual bool RecvloadURL(const nsCString& uri);