Allow fallback from https to http for component update checks.

ios/chrome/browser/component_updater/ios_component_updater_configurator.cc

 // 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.
 
 #include "ios/chrome/browser/component_updater/ios_component_updater_configurator.h"
 
 #include <string>
 #include <vector>
 
 #include "base/threading/sequenced_worker_pool.h"
@@ skipping 37 matching lines @@
       const override;
 
  private:
   friend class base::RefCountedThreadSafe<IOSConfigurator>;
 
   ConfiguratorImpl configurator_impl_;
 
   ~IOSConfigurator() override {}
 };
 
+// Allows the component updater to use non-encrypted communication with the
+// update backend. The security of the update checks is enforced using
+// a custom message signing protocol and it does not depend on using HTTPS.
 IOSConfigurator::IOSConfigurator(
     const base::CommandLine* cmdline,
     net::URLRequestContextGetter* url_request_getter)
-    : configurator_impl_(cmdline, url_request_getter) {}
+    : configurator_impl_(cmdline, url_request_getter, false) {}
 
 int IOSConfigurator::InitialDelay() const {
   return configurator_impl_.InitialDelay();
 }
 
 int IOSConfigurator::NextCheckDelay() const {
   return configurator_impl_.NextCheckDelay();
 }
 
 int IOSConfigurator::StepDelay() const {
@@ skipping 71 matching lines @@
 
 }  // namespace
 
 scoped_refptr<update_client::Configurator> MakeIOSComponentUpdaterConfigurator(
     const base::CommandLine* cmdline,
     net::URLRequestContextGetter* context_getter) {
   return new IOSConfigurator(cmdline, context_getter);
 }
 
 }  // namespace component_updater