Prerender Instant search base url on omnibox focus event

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 73 matching lines @@
 void OmniboxCurrentPageDelegateImpl::OnInputStateChanged() {
   if (!controller_->GetWebContents())
     return;
   SearchTabHelper::FromWebContents(
       controller_->GetWebContents())->OmniboxInputStateChanged();
 }
 
 void OmniboxCurrentPageDelegateImpl::OnFocusChanged(
     OmniboxFocusState state,
     OmniboxFocusChangeReason reason) {
-  if (!controller_->GetWebContents())
+  content::WebContents* web_contents = controller_->GetWebContents();
+  if (!web_contents)
     return;
-  SearchTabHelper::FromWebContents(
-      controller_->GetWebContents())->OmniboxFocusChanged(state, reason);
+
+  SearchTabHelper* tab_helper = SearchTabHelper::FromWebContents(web_contents);
+  tab_helper->OmniboxFocusChanged(state, reason);
+
+  if (chrome::ShouldPrerenderInstantUrlOnOmniboxFocus() &&
+      state == OMNIBOX_FOCUS_VISIBLE) {
+    gfx::Rect container_bounds = web_contents->GetContainerBounds();
+    InstantSearchPrerenderer* prerenderer =
+        InstantSearchPrerenderer::GetForProfile(profile_);
+    if (prerenderer && !tab_helper->IsSearchResultsPage()) {
+      prerenderer->Init(
+          web_contents->GetController().GetSessionStorageNamespaceMap(),
+          container_bounds.size());

[kmadhusu, 2014/06/17 18:29:35]

Let's start with a simple approach.

- When the omnibox gains focus, prerender the Instant search base page.
- When the omnibox loses focus, cancel the prerender request.

[sidharthms, 2014/06/17 21:52:24]

Done.

+    }
+  }
 }
 
 void OmniboxCurrentPageDelegateImpl::DoPrerender(
     const AutocompleteMatch& match) {
   content::WebContents* web_contents = controller_->GetWebContents();
   gfx::Rect container_bounds = web_contents->GetContainerBounds();
 
   InstantSearchPrerenderer* prerenderer =
       InstantSearchPrerenderer::GetForProfile(profile_);
   if (prerenderer && prerenderer->IsAllowed(match, web_contents)) {
@@ skipping 20 matching lines @@
       SearchTabHelper::FromWebContents(web_contents)->
           SetSuggestionToPrefetch(suggestion);
     }
   } else if (chrome::ShouldPrefetchSearchResults()) {
       InstantSearchPrerenderer* prerenderer =
           InstantSearchPrerenderer::GetForProfile(profile_);
       if (prerenderer)
         prerenderer->Prerender(suggestion);
   }
 }