Allow fallback from https to http for component update checks.

components/component_updater/default_component_installer.h

 // Copyright 2014 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_COMPONENT_UPDATER_DEFAULT_COMPONENT_INSTALLER_H_
 #define COMPONENTS_COMPONENT_UPDATER_DEFAULT_COMPONENT_INSTALLER_H_
 
 #include <stdint.h>
 #include <string>
 #include <vector>
@@ skipping 31 matching lines @@
   // Called only from a thread belonging to a blocking thread pool.
   // The implementation of this function must be efficient since the function
   // can be called when Chrome starts.
   virtual bool VerifyInstallation(const base::DictionaryValue& manifest,
                                   const base::FilePath& install_dir) const = 0;
 
   // Returns true if the component can be automatically updated. Called once
   // during component registration from the UI thread.
   virtual bool CanAutoUpdate() const = 0;
 
+  // Returns true if the network communication related to this component
+  // must be encrypted.
+  virtual bool RequiresNetworkEncryption() const = 0;
+
   // OnCustomInstall is called during the installation process. Components that
   // require custom installation operations should implement them here.
   // Returns false if a custom operation failed, and true otherwise.
   // Called only from a thread belonging to a blocking thread pool.
   virtual bool OnCustomInstall(const base::DictionaryValue& manifest,
                                const base::FilePath& install_dir) = 0;
 
   // ComponentReady is called in two cases:
   //   1) After an installation is successfully completed.
   //   2) During component registration if the component is already installed.
@@ skipping 64 matching lines @@
   scoped_refptr<base::SingleThreadTaskRunner> main_task_runner_;
 
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(DefaultComponentInstaller);
 };
 
 }  // namespace component_updater
 
 #endif  // COMPONENTS_COMPONENT_UPDATER_DEFAULT_COMPONENT_INSTALLER_H_