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

components/omnibox/browser/omnibox_popup_model.cc

Index: components/omnibox/browser/omnibox_popup_model.cc
diff --git a/components/omnibox/browser/omnibox_popup_model.cc b/components/omnibox/browser/omnibox_popup_model.cc
index 6fa120ea775bdbb75d6b7e213480eedb931b4f26..239a3bcedd63b62a6f3447c78cd69e876aad3a49 100644
--- a/components/omnibox/browser/omnibox_popup_model.cc
+++ b/components/omnibox/browser/omnibox_popup_model.cc
@@ -6,11 +6,13 @@
 
 #include <algorithm>
 
+#include "base/feature_list.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "components/bookmarks/browser/bookmark_model.h"
 #include "components/omnibox/browser/autocomplete_match.h"
 #include "components/omnibox/browser/omnibox_client.h"
+#include "components/omnibox/browser/omnibox_field_trial.h"
 #include "components/omnibox/browser/omnibox_popup_model_observer.h"
 #include "components/omnibox/browser/omnibox_popup_view.h"
 #include "components/search_engines/template_url.h"
@@ -55,8 +57,10 @@ void OmniboxPopupModel::ComputeMatchMaxWidths(int contents_width,
 
   // If the description is empty, or the contents and description are on
   // separate lines, each can get the full available width.
-  if (!description_width || description_on_separate_line)
+  if (!description_width || description_on_separate_line ||

[Peter Kasting, 2017/05/25 20:24:39]

I feel like the caller should have passed true for
|description_on_separate_line|, rather than checking it internally here.

This would also make for better testability, since you can specify the behavior
you want directly in the test.

[tommycli, 2017/05/25 21:59:10]

Done.

+      base::FeatureList::IsEnabled(omnibox::kUIExperimentVerticalLayout)) {

[Peter Kasting, 2017/05/25 20:24:39]

Nit: Omnibox code doesn't usually use braces for cases like this

[tommycli, 2017/05/25 21:59:10]

Done.

     return;
+  }
 
   // If we want to display the description, we need to reserve enough space for
   // the separator.