Prerender: Add kSupportSearchSuggestionForPrerender2 to chrome://flags

This CL allows users to enable DSE prerender on chrome://flags, which
makes it easier to try this feature. :)

Bug: 1278634
Change-Id: Ibe0d77e5396bc1360e20fc7c39f219a7cb7f8711
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3470350
Reviewed-by: Hiroki Nakagawa <[email protected]>
Commit-Queue: Lingqi Chi <[email protected]>
Cr-Commit-Position: refs/heads/main@{#972802}
diff --git a/chrome/browser/flag_descriptions.cc b/chrome/browser/flag_descriptions.cc
index 098c042..bdda6818 100644
--- a/chrome/browser/flag_descriptions.cc
+++ b/chrome/browser/flag_descriptions.cc
@@ -2146,6 +2146,12 @@
 const char kOmniboxTriggerForPrerender2Description[] =
     "Enables the new omnibox trigger prerenderer implementation.";
 
+const char kSupportSearchSuggestionForPrerender2Name[] =
+    "Prerender search suggestions";
+const char kSupportSearchSuggestionForPrerender2Description[] =
+    "Allows Prerender2 to prerender search suggestions provided by the default "
+    "search engine. Requires chrome://flags/#enable-prerender2 to be enabled";
+
 const char kPrivacyAdvisorName[] = "Privacy Advisor";
 const char kPrivacyAdvisorDescription[] =
     "Provides contextual entry points for adjusting privacy settings";