First pass at experimental omnibox API. There are plenty of rough edges and

chrome/browser/search_engines/template_url.h

Index: chrome/browser/search_engines/template_url.h
diff --git a/chrome/browser/search_engines/template_url.h b/chrome/browser/search_engines/template_url.h
index 1a7d77902732fb8cf9ffc6af243629c5ce497db9..40561ac3ec00726544ff366fde08a630b5437da6 100644
--- a/chrome/browser/search_engines/template_url.h
+++ b/chrome/browser/search_engines/template_url.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 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.
 
@@ -421,6 +421,9 @@ class TemplateURL {
   void set_prepopulate_id(int id) { prepopulate_id_ = id; }
   int prepopulate_id() const { return prepopulate_id_; }
 
+  std::string GetExtensionId() const;
+  bool IsExtensionKeyword() const;
+
  private:
   friend class WebDatabaseTest;
   friend class WebDatabase;