DO NOT MERGE: Make update_engine compile in the branch.

These changes are required to adapt the cherry-picked CLs to the
context of this branch.

Bug: 27178350
Change-Id: Ifb6be225294e5b8849daa2dce90cc952ef2dab52
diff --git a/sideload_main.cc b/sideload_main.cc
index 46e8f35..43d0f93 100644
--- a/sideload_main.cc
+++ b/sideload_main.cc
@@ -139,7 +139,8 @@
                         int64_t payload_size,
                         const vector<string>& headers,
                         int64_t status_fd) {
-  brillo::BaseMessageLoop loop;
+  base::MessageLoopForIO base_loop;
+  brillo::BaseMessageLoop loop(&base_loop);
   loop.SetAsCurrent();
 
   // Setup the subprocess handler.