Omnibox UI Experiments: Add Vertical Layout experiment (title-on-top).

components/omnibox/browser/omnibox_field_trial.cc

Index: components/omnibox/browser/omnibox_field_trial.cc
diff --git a/components/omnibox/browser/omnibox_field_trial.cc b/components/omnibox/browser/omnibox_field_trial.cc
index f73625412a28e18887f8ed3f6f706db14526e5c0..1e406814836a7bffe47f448fe36eeee664e758d5 100644
--- a/components/omnibox/browser/omnibox_field_trial.cc
+++ b/components/omnibox/browser/omnibox_field_trial.cc
@@ -87,6 +87,10 @@ const base::Feature kUIExperimentMaxAutocompleteMatches{
     base::FEATURE_DISABLED_BY_DEFAULT};
 
 // Feature used for the vertical margin UI experiment.
+const base::Feature kUIExperimentVerticalLayout{
+    "OmniboxUIExperimentVerticalLayout", base::FEATURE_DISABLED_BY_DEFAULT};
+
+// Feature used for the vertical margin UI experiment.
 const base::Feature kUIExperimentVerticalMargin{
     "OmniboxUIExperimentVerticalMargin", base::FEATURE_DISABLED_BY_DEFAULT};