Set up a field trial flag to prerender Instant search base url on omnibox focus event.

chrome/browser/search/search.cc

Index: chrome/browser/search/search.cc
diff --git a/chrome/browser/search/search.cc b/chrome/browser/search/search.cc
index 7e01ef48eea42ccba507c17d2dc1b34247d769fa..2294bdd9dddb91e77abce9debf5e0d7f46e90c12 100644
--- a/chrome/browser/search/search.cc
+++ b/chrome/browser/search/search.cc
@@ -66,6 +66,8 @@ const uint64 kEmbeddedPageVersionDefault = 2;
 const char kHideVerbatimFlagName[] = "hide_verbatim";
 const char kPrefetchSearchResultsFlagName[] = "prefetch_results";
 const char kPrefetchSearchResultsOnSRP[] = "prefetch_results_srp";
+const char kPrerenderInstantUrlOnOmniboxFocus[] =
+    "prerender_instant_url_on_omnibox_focus";
 
 // Controls whether to reuse prerendered Instant Search base page to commit any
 // search query.
@@ -576,6 +578,16 @@ bool ShouldPrefetchSearchResults() {
       kPrefetchSearchResultsFlagName, false, flags);
 }
 
+bool ShouldPrerenderInstantUrlOnOmniboxFocus() {
+  if (!ShouldPrefetchSearchResults())
+    return false;
+
+  FieldTrialFlags flags;
+  return GetFieldTrialInfo(&flags) &&
+      GetBoolValueForFlagWithDefault(

[kmadhusu, 2014/06/12 23:59:15]

nit: This can go the previous line as follows:

return GetFieldTrialInfo(&flags) && GetBoolValueForFlagWithDefault(
     kPrerenderInstantUrlOnOmniboxFocus, false, flags);

[sidharthms, 2014/06/13 00:17:55]

Done.

+          kPrerenderInstantUrlOnOmniboxFocus, false, flags);
+}
+
 bool ShouldReuseInstantSearchBasePage() {
   if (CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kPrefetchSearchResults)) {