Track the active ExtensionKeybindingRegistry and make it available to EventRewriter.

chrome/test/base/test_browser_window.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/test/base/test_browser_window.h"
 
 #include "chrome/browser/ui/browser_list.h"
 #include "chrome/browser/ui/browser_list_observer.h"
 #include "ui/gfx/rect.h"
 
@@ skipping 205 matching lines @@
 }
 
 int
 TestBrowserWindow::GetRenderViewHeightInsetWithDetachedBookmarkBar() {
   return 0;
 }
 
 void TestBrowserWindow::ExecuteExtensionCommand(
     const extensions::Extension* extension,
     const extensions::Command& command) {}
+
+bool TestBrowserWindow::IsExtensionCommandRegistered(
+    const ui::Accelerator& accelerator) {
+  return false;
+}