Allow fallback from https to http for component update checks.

components/update_client/update_checker.cc

Index: components/update_client/update_checker.cc
diff --git a/components/update_client/update_checker.cc b/components/update_client/update_checker.cc
index dd851d9baf0d6ca059936ef4b704ebb0ae341b67..f398d003728a4fe67e2285233589e87ba922b4cf 100644
--- a/components/update_client/update_checker.cc
+++ b/components/update_client/update_checker.cc
@@ -85,7 +85,9 @@ class UpdateCheckerImpl : public UpdateChecker {
       const UpdateCheckCallback& update_check_callback) override;
 
  private:
-  void OnRequestSenderComplete(int error, const std::string& response);
+  void OnRequestSenderComplete(int error,
+                               const std::string& response,
+                               int retry_after_sec);
   base::ThreadChecker thread_checker_;
 
   const scoped_refptr<Configurator> config_;
@@ -126,15 +128,16 @@ bool UpdateCheckerImpl::CheckForUpdates(
 }
 
 void UpdateCheckerImpl::OnRequestSenderComplete(int error,
-                                                const std::string& response) {
+                                                const std::string& response,
+                                                int retry_after_sec) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   if (!error) {
     UpdateResponse update_response;
     if (update_response.Parse(response)) {
       base::ThreadTaskRunnerHandle::Get()->PostTask(
-          FROM_HERE,
-          base::Bind(update_check_callback_, error, update_response.results()));
+          FROM_HERE, base::Bind(update_check_callback_, error,
+                                update_response.results(), retry_after_sec));
       return;
     }
 
@@ -143,8 +146,8 @@ void UpdateCheckerImpl::OnRequestSenderComplete(int error,
   }
 
   base::ThreadTaskRunnerHandle::Get()->PostTask(
-      FROM_HERE,
-      base::Bind(update_check_callback_, error, UpdateResponse::Results()));
+      FROM_HERE, base::Bind(update_check_callback_, error,
+                            UpdateResponse::Results(), retry_after_sec));
 }
 
 }  // namespace