Adds a chrome://flags/#omnibox-on-focus-suggestions

- Adds a flag to chrome://flags to control omnibox::kOnFocusSuggestions.
- Adds a variation to the flag entry that allows enabling zero-prefix
  suggestions in the NTP Realbox.

Bug: 996516
Change-Id: Ia501cf6951a591130e9845c57e90f889b7b33c6f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1775581
Commit-Queue: Moe Ahmadi <[email protected]>
Reviewed-by: Avi Drissman <[email protected]>
Reviewed-by: Tommy Li <[email protected]>
Cr-Commit-Position: refs/heads/master@{#692238}
diff --git a/chrome/browser/flag_descriptions.cc b/chrome/browser/flag_descriptions.cc
index bd1039756..87d4934 100644
--- a/chrome/browser/flag_descriptions.cc
+++ b/chrome/browser/flag_descriptions.cc
@@ -1350,6 +1350,11 @@
     "Use material design weather icons in the omnibox when displaying weather "
     "answers.";
 
+const char kOmniboxOnFocusSuggestionsName[] = "Omnibox on-focus suggestions";
+const char kOmniboxOnFocusSuggestionsDescription[] =
+    "Configures Omnibox on-focus suggestions - suggestions displayed on-focus "
+    "before the user has typed any input";
+
 const char kOmniboxRichEntitySuggestionsName[] =
     "Omnibox rich entity suggestions";
 const char kOmniboxRichEntitySuggestionsDescription[] =