Register external extension providers also for supervised users.

Not registering them broke voice search for supervised users, because the corresponding extension comes from one of these providers.
It also resulted in inconsistent behavior for child accounts, where the providers would exist after the first sign-in, but not after the next browser restart.

BUG=458096,397951

Review URL: https://codereview.chromium.org/955683002

Cr-Commit-Position: refs/heads/master@{#318670}

chrome/browser/extensions/external_provider_impl.cc

@@ -498,7 +498,7 @@ void ExternalProviderImpl::CreateExternalProviders(
                                  oem_extension_creation_flags)));
   }
 #elif defined(OS_LINUX)
-  if (!profile->IsSupervised()) {
+  if (!profile->IsLegacySupervised()) {
     provider_list->push_back(
         linked_ptr<ExternalProviderInterface>(
             new ExternalProviderImpl(
@@ -514,7 +514,7 @@ void ExternalProviderImpl::CreateExternalProviders(
   }
 #endif
 
-  if (!profile->IsSupervised()) {
+  if (!profile->IsLegacySupervised()) {
 #if defined(OS_WIN)
     provider_list->push_back(
         linked_ptr<ExternalProviderInterface>(
@@ -570,17 +570,17 @@ void ExternalProviderImpl::CreateExternalProviders(
                 Extension::FROM_WEBSTORE |
                     Extension::WAS_INSTALLED_BY_DEFAULT)));
 #endif
-
-    provider_list->push_back(
-      linked_ptr<ExternalProviderInterface>(
-        new ExternalProviderImpl(
-            service,
-            new ExternalComponentLoader(profile),
-            profile,
-            Manifest::INVALID_LOCATION,
-            Manifest::EXTERNAL_COMPONENT,
-            Extension::FROM_WEBSTORE | Extension::WAS_INSTALLED_BY_DEFAULT)));
   }
+
+  provider_list->push_back(
+    linked_ptr<ExternalProviderInterface>(
+      new ExternalProviderImpl(
+          service,
+          new ExternalComponentLoader(profile),
+          profile,
+          Manifest::INVALID_LOCATION,
+          Manifest::EXTERNAL_COMPONENT,
+          Extension::FROM_WEBSTORE | Extension::WAS_INSTALLED_BY_DEFAULT)));
 }
 
 }  // namespace extensions