Enable prefetch-search-results on Desktop Chrome by default.

chrome/browser/ui/omnibox/omnibox_current_page_delegate_impl.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/omnibox/omnibox_current_page_delegate_impl.h"
 
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/autocomplete/autocomplete_match.h"
 #include "chrome/browser/extensions/api/omnibox/omnibox_api.h"
 #include "chrome/browser/predictors/autocomplete_action_predictor.h"
@@ skipping 102 matching lines @@
 
   predictors::AutocompleteActionPredictorFactory::GetForProfile(profile_)->
       StartPrerendering(
           match.destination_url,
           web_contents->GetController().GetSessionStorageNamespaceMap(),
           container_bounds.size());
 }
 
 void OmniboxCurrentPageDelegateImpl::SetSuggestionToPrefetch(
       const InstantSuggestion& suggestion) {
+  DCHECK(chrome::IsInstantExtendedAPIEnabled());
   content::WebContents* web_contents = controller_->GetWebContents();
   if (web_contents &&
       SearchTabHelper::FromWebContents(web_contents)->IsSearchResultsPage()) {
-    if (chrome::ShouldPrefetchSearchResultsOnSRP() ||
-        chrome::ShouldPrefetchSearchResults()) {
+    if (chrome::ShouldPrefetchSearchResultsOnSRP()) {
       SearchTabHelper::FromWebContents(web_contents)->
           SetSuggestionToPrefetch(suggestion);
     }
-  } else if (chrome::ShouldPrefetchSearchResults()) {
-      InstantSearchPrerenderer* prerenderer =
-          InstantSearchPrerenderer::GetForProfile(profile_);
-      if (prerenderer)
-        prerenderer->Prerender(suggestion);
+  } else {
+    InstantSearchPrerenderer* prerenderer =
+        InstantSearchPrerenderer::GetForProfile(profile_);
+    if (prerenderer)
+      prerenderer->Prerender(suggestion);
   }
 }