[CrOS Settings] Add missing toggle to "Sync and Google Services" subpage

Add missing "Google Drive Search Suggestion" ("Chrome [browser] will
access your drive to make search suggestions in the address bar")
toggle to "Sync and Google Services".

SplitSettingsSync must be disabled and "Omnibox Google drive document
suggestions" flag must be enabled to see this change.

When both flags are set to default, there is no visible impact.

https://screenshot.googleplex.com/NPiR2gTUVKT

Bug: 1083029
Change-Id: Idbfcb7bb3f287fbcc5ffa8a333f39c2aef9cdc6a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2213931
Commit-Queue: Regan Hsu <hsuregan@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#772068}

chrome/browser/ui/webui/settings/chromeos/people_section.cc

@@ -40,6 +40,7 @@
 #include "chromeos/constants/chromeos_features.h"
 #include "chromeos/constants/chromeos_pref_names.h"
 #include "components/google/core/common/google_util.h"
+#include "components/omnibox/common/omnibox_features.h"
 #include "components/prefs/pref_service.h"
 #include "components/sync/driver/sync_service.h"
 #include "components/sync/driver/sync_user_settings.h"
@@ -714,6 +715,10 @@ void PeopleSection::AddLoadTimeData(content::WebUIDataSource* html_source) {
   html_source->AddBoolean("isEduCoexistenceEnabled",
                           ::chromeos::features::IsEduCoexistenceEnabled());
 
+  html_source->AddBoolean(
+      "driveSuggestAvailable",
+      base::FeatureList::IsEnabled(omnibox::kDocumentProvider));
+
   AddAccountManagerPageStrings(html_source);
   AddKerberosAccountsPageStrings(html_source);
   AddKerberosAddAccountDialogStrings(html_source);