[omnibox] Add kFocusGestureTriggersContextualWebZeroSuggest flag

This CL adds an enabled-by-default flag that causes on-focus gestures
to trigger ZeroSuggest on the Contextual Web page classification
(OTHER).

We add this flag so we can disable it in some experiments, where we
want to use on-clobber instead.

It also adds a test to make sure this flag doesn't affect other page
classifications such as the NTP.

Bug: 1106096
Change-Id: I32d4b9fc396874f836c60ae347ac3894818cf1d1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2350309
Commit-Queue: Tommy Li <[email protected]>
Reviewed-by: Justin Donnelly <[email protected]>
Cr-Commit-Position: refs/heads/master@{#797491}
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 10f412b..926c67b 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -3660,6 +3660,15 @@
      flag_descriptions::kOmniboxClobberIsZeroSuggestEntrypointDescription,
      kOsAll, FEATURE_VALUE_TYPE(omnibox::kClobberIsZeroSuggestEntrypoint)},
 
+    {"omnibox-focus-gesture-triggers-contextual-web-zero-suggest",
+     flag_descriptions::
+         kOmniboxFocusGestureTriggersContextualWebZeroSuggestName,
+     flag_descriptions::
+         kOmniboxFocusGestureTriggersContextualWebZeroSuggestDescription,
+     kOsAll,
+     FEATURE_VALUE_TYPE(
+         omnibox::kFocusGestureTriggersContextualWebZeroSuggest)},
+
     {"omnibox-on-device-head-suggestions-incognito",
      flag_descriptions::kOmniboxOnDeviceHeadSuggestionsIncognitoName,
      flag_descriptions::kOmniboxOnDeviceHeadSuggestionsIncognitoDescription,