Use PreloadCheckGroup in ExtensionInstallChecker. Make RequirementsChecker a PreloadCheck.

extensions/browser/preload_check_group.cc

Index: extensions/browser/preload_check_group.cc
diff --git a/extensions/browser/preload_check_group.cc b/extensions/browser/preload_check_group.cc
index 1dc332f4451472ff9d87e99888e99eef4b70e535..6c029a354328f9ada5f7d211980e939d3ad1c2db 100644
--- a/extensions/browser/preload_check_group.cc
+++ b/extensions/browser/preload_check_group.cc
@@ -32,9 +32,9 @@ void PreloadCheckGroup::Start(ResultCallback callback) {
 
   running_checks_ = checks_.size();
   for (auto* check : checks_) {
-    check->Start(base::Bind(&PreloadCheckGroup::OnCheckComplete,
-                            weak_ptr_factory_.GetWeakPtr(), check,
-                            current_sequence_number_));
+    check->Start(base::BindOnce(&PreloadCheckGroup::OnCheckComplete,
+                                weak_ptr_factory_.GetWeakPtr(), check,
+                                current_sequence_number_));
     // Synchronous checks may fail immediately.
     if (running_checks_ == 0)
       return;