shortcuts: Add flag "enable-search-in-shortcuts-app"

This flag will be used to gate the new search UI in the new shortcuts
app.

Bug: b:266085562
Change-Id: I07eabe212ae47ac762e3e33ab33043bffc20b237
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4237195
Commit-Queue: Camden Bickel <[email protected]>
Reviewed-by: Jimmy Gong <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1103448}
diff --git a/chrome/browser/flag_descriptions.cc b/chrome/browser/flag_descriptions.cc
index bfc3c821..14ed950 100644
--- a/chrome/browser/flag_descriptions.cc
+++ b/chrome/browser/flag_descriptions.cc
@@ -1098,6 +1098,11 @@
 extern const char kEnableShortcutCustomizationDescription[] =
     "Enable customization of shortcuts in the new shortcuts app.";
 
+extern const char kEnableSearchInShortcutsAppName[] =
+    "Enable search in new shortcuts app";
+extern const char kEnableSearchInShortcutsAppDescription[] =
+    "Enable searching for shortcuts in the new shortcuts app.";
+
 const char kEnableInputDeviceSettingsSplitName[] =
     "Enable input device settings split";
 const char kEnableInputDeviceSettingsSplitDescription[] =