Revert of [Extensions] Enable sideloading prompt on mac on canary

chrome/browser/extensions/extension_service.cc

 // Copyright (c) 2013 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 "chrome/browser/extensions/extension_service.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <iterator>
@@ skipping 2240 matching lines @@
   // remain disabled.
   if (extension_prefs_->IsExtensionDisabled(extension->id())) {
     int disable_reasons = extension_prefs_->GetDisableReasons(extension->id());
     // If an extension was disabled without specified reason, presume it's
     // disabled by user.
     return disable_reasons == Extension::DISABLE_NONE
                ? Extension::DISABLE_USER_ACTION
                : disable_reasons;
   }
 
-  if (extensions::ExternalInstallManager::IsPromptingEnabled()) {
+  if (FeatureSwitch::prompt_for_external_extensions()->IsEnabled()) {
     // External extensions are initially disabled. We prompt the user before
     // enabling them. Hosted apps are excepted because they are not dangerous
     // (they need to be launched by the user anyway). We also don't prompt for
     // extensions updating; this is because the extension will be disabled from
     // the initial install if it is supposed to be, and this allows us to turn
     // this on for other platforms without disabling already-installed
     // extensions.
     if (extension->GetType() != Manifest::TYPE_HOSTED_APP &&
         Manifest::IsExternalLocation(extension->location()) &&
         !extension_prefs_->IsExternalExtensionAcknowledged(extension->id()) &&
@@ skipping 218 matching lines @@
 }
 
 void ExtensionService::OnProfileDestructionStarted() {
   ExtensionIdSet ids_to_unload = registry_->enabled_extensions().GetIDs();
   for (ExtensionIdSet::iterator it = ids_to_unload.begin();
        it != ids_to_unload.end();
        ++it) {
     UnloadExtension(*it, UnloadedExtensionInfo::REASON_PROFILE_SHUTDOWN);
   }
 }