diff -r 000000000000 -r 6474c204b198 embedding/browser/webBrowser/nsCommandHandler.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/embedding/browser/webBrowser/nsCommandHandler.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,147 @@
+/* -*- Mode: C++; tab-width: 4; 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 "nsCommandHandler.h"
+#include "nsWebBrowser.h"
+#include "nsDocShellTreeOwner.h"
+
+#include "nsMemory.h"
+#include "nsPIDOMWindow.h"
+
+nsCommandHandler::nsCommandHandler() :
+    mWindow(nullptr)
+{
+}
+
+nsCommandHandler::~nsCommandHandler()
+{
+}
+
+nsresult nsCommandHandler::GetCommandHandler(nsICommandHandler **aCommandHandler)
+{
+    NS_ENSURE_ARG_POINTER(aCommandHandler);
+
+    *aCommandHandler = nullptr;
+    if (mWindow == nullptr)
+    {
+        return NS_ERROR_FAILURE;
+    }
+
+    nsCOMPtr<nsPIDOMWindow> window(do_QueryInterface(mWindow));
+    if (!window)
+    {
+        return NS_ERROR_FAILURE;
+    }
+
+    // Get the document tree owner
+
+    nsCOMPtr<nsIDocShellTreeItem> docShellAsTreeItem =
+      do_QueryInterface(window->GetDocShell());
+    nsIDocShellTreeOwner *treeOwner = nullptr;
+    docShellAsTreeItem->GetTreeOwner(&treeOwner);
+
+    // Make sure the tree owner is an an nsDocShellTreeOwner object
+    // by QI'ing for a hidden interface. If it doesn't have the interface
+    // then it's not safe to do the casting.
+
+    nsCOMPtr<nsICDocShellTreeOwner> realTreeOwner(do_QueryInterface(treeOwner));
+    if (realTreeOwner)
+    {
+        nsDocShellTreeOwner *tree = static_cast<nsDocShellTreeOwner *>(treeOwner);
+        if (tree->mTreeOwner)
+        {
+            nsresult rv;
+            rv = tree->mTreeOwner->QueryInterface(NS_GET_IID(nsICommandHandler), (void **)aCommandHandler);
+            NS_RELEASE(treeOwner);
+            return rv;
+        }
+     
+        NS_RELEASE(treeOwner);
+     }
+
+    *aCommandHandler = nullptr;
+
+    return NS_OK;
+}
+
+
+NS_IMPL_ADDREF(nsCommandHandler)
+NS_IMPL_RELEASE(nsCommandHandler)
+
+NS_INTERFACE_MAP_BEGIN(nsCommandHandler)
+    NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsICommandHandler)
+    NS_INTERFACE_MAP_ENTRY(nsICommandHandlerInit)
+    NS_INTERFACE_MAP_ENTRY(nsICommandHandler)
+NS_INTERFACE_MAP_END
+
+///////////////////////////////////////////////////////////////////////////////
+// nsICommandHandlerInit implementation
+
+/* attribute nsIDocShell docShell; */
+NS_IMETHODIMP nsCommandHandler::GetWindow(nsIDOMWindow * *aWindow)
+{
+    *aWindow = nullptr;
+    return NS_OK;
+}
+
+NS_IMETHODIMP nsCommandHandler::SetWindow(nsIDOMWindow * aWindow)
+{
+    if (aWindow == nullptr)
+    {
+       return NS_ERROR_FAILURE;
+    }
+    mWindow = aWindow;
+    return NS_OK;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// nsICommandHandler implementation
+
+/* string exec (in string aCommand, in string aStatus); */
+NS_IMETHODIMP nsCommandHandler::Exec(const char *aCommand, const char *aStatus, char **aResult)
+{
+    NS_ENSURE_ARG_POINTER(aCommand);
+    NS_ENSURE_ARG_POINTER(aResult);
+
+    nsCOMPtr<nsICommandHandler> commandHandler;
+    GetCommandHandler(getter_AddRefs(commandHandler));
+
+    // Call the client's command handler to deal with this command
+    if (commandHandler)
+    {
+        *aResult = nullptr;
+        return commandHandler->Exec(aCommand, aStatus, aResult);
+    }
+
+    // Return an empty string
+    const char szEmpty[] = "";
+    *aResult = (char *) nsMemory::Clone(szEmpty, sizeof(szEmpty));
+
+    return NS_OK;
+}
+
+/* string query (in string aCommand, in string aStatus); */
+NS_IMETHODIMP nsCommandHandler::Query(const char *aCommand, const char *aStatus, char **aResult)
+{
+    NS_ENSURE_ARG_POINTER(aCommand);
+    NS_ENSURE_ARG_POINTER(aResult);
+
+    nsCOMPtr<nsICommandHandler> commandHandler;
+    GetCommandHandler(getter_AddRefs(commandHandler));
+
+    // Call the client's command handler to deal with this command
+    if (commandHandler)
+    {
+        *aResult = nullptr;
+        return commandHandler->Query(aCommand, aStatus, aResult);
+    }
+
+    // Return an empty string
+    const char szEmpty[] = "";
+    *aResult = (char *) nsMemory::Clone(szEmpty, sizeof(szEmpty));
+
+    return NS_OK;
+}