Enforce the 'requirements' field in manifests.

chrome/common/extensions/extension.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_COMMON_EXTENSIONS_EXTENSION_H_
 #define CHROME_COMMON_EXTENSIONS_EXTENSION_H_
 #pragma once
 
 #include <algorithm>
 #include <iosfwd>
@@ skipping 34 matching lines @@
 
 namespace webkit_glue {
 struct WebIntentServiceData;
 }
 
 FORWARD_DECLARE_TEST(TabStripModelTest, Apps);
 
 namespace extensions {
 
 class Manifest;
+class RequirementsProvider;
 
 // Represents a Chrome extension.
 class Extension : public base::RefCountedThreadSafe<Extension> {
  public:
   struct InstallWarning;
 
   typedef std::map<const std::string, GURL> URLOverrideMap;
   typedef std::vector<std::string> ScriptingWhitelist;
   typedef std::vector<linked_ptr<FileBrowserHandler> > FileBrowserHandlerList;
   typedef std::vector<InstallWarning> InstallWarningVector;
@@ skipping 1111 matching lines @@
   // only the permissions that have added, and for Reason::REMOVED, this would
   // only contain the removed permissions.
   const PermissionSet* permissions;
 
   UpdatedExtensionPermissionsInfo(
       const Extension* extension,
       const PermissionSet* permissions,
       Reason reason);
 };
 
-} // namespace extensions
+}  // namespace extensions
 
 #endif  // CHROME_COMMON_EXTENSIONS_EXTENSION_H_