Add an experimental standalone content suggestions UI.

chrome/browser/android/chrome_feature_list.cc

Index: chrome/browser/android/chrome_feature_list.cc
diff --git a/chrome/browser/android/chrome_feature_list.cc b/chrome/browser/android/chrome_feature_list.cc
index a04b5f45c7f627856d06ee96addd2e61cfc89215..5d399dcc526628f83f62324f5d5b7cd2b5fc78f3 100644
--- a/chrome/browser/android/chrome_feature_list.cc
+++ b/chrome/browser/android/chrome_feature_list.cc
@@ -51,6 +51,7 @@ const base::Feature* kFeaturesExposedToJava[] = {
     &kNoCreditCardAbort,
     &kNTPFakeOmniboxTextFeature,
     &kNTPOfflinePagesFeature,
+    &kNTPSuggestionsStandaloneUIFeature,
     &kPhysicalWebFeature,
     &kPhysicalWebIgnoreOtherClientsFeature,
     &kSpecialLocaleFeature,
@@ -113,6 +114,9 @@ const base::Feature kNTPFakeOmniboxTextFeature{
 const base::Feature kNTPOfflinePagesFeature{"NTPOfflinePages",
                                             base::FEATURE_ENABLED_BY_DEFAULT};
 
+const base::Feature kNTPSuggestionsStandaloneUIFeature{
+    "NTPSuggestionsStandaloneUI", base::FEATURE_DISABLED_BY_DEFAULT};
+
 const base::Feature kPhysicalWebFeature{"PhysicalWeb",
                                         base::FEATURE_ENABLED_BY_DEFAULT};