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

chrome/browser/about_flags.cc

Index: chrome/browser/about_flags.cc
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 5e67680d68f9b5045acc288986b4dbfdbf0c6ba7..acba62e8e451ec4f934be761f5bf987408245301 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -2953,6 +2953,11 @@ const FeatureEntry kFeatureEntries[] = {
          kOmniboxUIMaxAutocompleteMatchesVariations,
          "OmniboxUIMaxAutocompleteVariations")},
 
+    {"omnibox-ui-vertical-layout",
+     flag_descriptions::kOmniboxUIVerticalLayoutName,
+     flag_descriptions::kOmniboxUIVerticalLayoutDescription, kOsDesktop,
+     FEATURE_VALUE_TYPE(omnibox::kUIExperimentVerticalLayout)},
+
     {"omnibox-ui-vertical-margin",
      flag_descriptions::kOmniboxUIVerticalMarginName,
      flag_descriptions::kOmniboxUIVerticalMarginDescription, kOsDesktop,