Introduce Zero Prefix URL Suggestions flag.

This flag controls support for Omnibox Zero Prefix URL Suggestions on Clank.
When enabled, Omnibox will start supplying suggestions for currently visited
website.

Bug: 934922
Change-Id: Ic28e81855198c5a21e1c0e2eeee02629f422ca1f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1516713
Reviewed-by: Filip Gorski <[email protected]>
Reviewed-by: Matthew Jones <[email protected]>
Reviewed-by: Mark Pearson <[email protected]>
Commit-Queue: Ender <[email protected]>
Cr-Commit-Position: refs/heads/master@{#641327}
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index a20c1349..cf3e304 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -2886,6 +2886,13 @@
      flag_descriptions::kOmniboxUIUnboldSuggestionTextDescription, kOsDesktop,
      FEATURE_VALUE_TYPE(omnibox::kUIExperimentUnboldSuggestionText)},
 
+#if defined(OS_ANDROID)
+    {"omnibox-zero-suggestions-on-ntp",
+     flag_descriptions::kOmniboxZeroSuggestionsOnNTPName,
+     flag_descriptions::kOmniboxZeroSuggestionsOnNTPDescription, kOsAndroid,
+     FEATURE_VALUE_TYPE(omnibox::kZeroSuggestionsOnNTP)},
+#endif
+
     {"omnibox-material-design-weather-icons",
      flag_descriptions::kOmniboxMaterialDesignWeatherIconsName,
      flag_descriptions::kOmniboxMaterialDesignWeatherIconsDescription,