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..80d89f34ef112588943c23d297745d474ba1e0a9 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 kPrerenderInstantSearchBaseOnFocus[] =
+    "prerender_instant_search_base_on_focus";

[kmadhusu, 2014/06/12 21:12:38]

How about prerender_instant_search_page_on_omnibox_focus?

[sidharthms, 2014/06/12 23:33:34]

Done.

 
 // Controls whether to reuse prerendered Instant Search base page to commit any
 // search query.
@@ -576,6 +578,13 @@ bool ShouldPrefetchSearchResults() {
       kPrefetchSearchResultsFlagName, false, flags);
 }
 
+bool ShouldPrerenderInstantSearchBaseOnFocus() {
+  FieldTrialFlags flags;

[kmadhusu, 2014/06/12 21:12:38]

We should prerender Instant Search base page only when "prefetch-search-results"
command line flag is specified or prefetch_results field trial flag is enabled.

[sidharthms, 2014/06/12 23:33:34]

Done.

+  return GetFieldTrialInfo(&flags) &&
+         GetBoolValueForFlagWithDefault(

[kmadhusu, 2014/06/12 21:12:38]

style nit: 4 space indentation.

[sidharthms, 2014/06/12 23:33:34]

Done.

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