Allow fallback from https to http for component update checks.

components/update_client/action_update_check.h

 // Copyright 2015 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 COMPONENTS_UPDATE_CLIENT_ACTION_UPDATE_CHECK_H_
 #define COMPONENTS_UPDATE_CLIENT_ACTION_UPDATE_CHECK_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 18 matching lines @@
  public:
   ActionUpdateCheck(scoped_ptr<UpdateChecker> update_checker,
                     const base::Version& browser_version,
                     const std::string& extra_request_parameters);
 
   ~ActionUpdateCheck() override;
 
   void Run(UpdateContext* update_context, Callback callback) override;
 
  private:
-  void UpdateCheckComplete(int error, const UpdateResponse::Results& results);
+  void UpdateCheckComplete(int error,
+                           const UpdateResponse::Results& results,
+                           int retry_after_sec);
 
   void OnUpdateCheckSucceeded(const UpdateResponse::Results& results);
   void OnUpdateCheckFailed(int error);
 
   scoped_ptr<UpdateChecker> update_checker_;
   const base::Version browser_version_;
   const std::string extra_request_parameters_;
 
   DISALLOW_COPY_AND_ASSIGN(ActionUpdateCheck);
 };
 
 }  // namespace update_client
 
 #endif  // COMPONENTS_UPDATE_CLIENT_ACTION_UPDATE_CHECK_H_