Initial unit tests for the discovery API.

chrome/browser/extensions/api/discovery/suggested_links_registry.h

 // 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.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_API_DISCOVERY_SUGGESTED_LINKS_REGISTRY_H_
 #define CHROME_BROWSER_EXTENSIONS_API_DISCOVERY_SUGGESTED_LINKS_REGISTRY_H_
 #pragma once
 
 #include <map>
 
@@ skipping 30 matching lines @@
   // Maps extension id to a list of notifications for that extension.
   typedef std::map<std::string, SuggestedLinkList> SuggestedLinksMap;
 
   virtual ~SuggestedLinksRegistry();
 
   // Gets suggested links for a given extension id.
   SuggestedLinkList& GetAllInternal(const std::string& extension_id);
 
   SuggestedLinksMap suggested_links_;
 
+  // An empty list of suggestions that can be returned for non-existing
+  // extensions.
+  SuggestedLinkList empty_list_;
+
   DISALLOW_COPY_AND_ASSIGN(SuggestedLinksRegistry);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_DISCOVERY_SUGGESTED_LINKS_REGISTRY_H_