Prerender Instant search base url on omnibox focus event

chrome/browser/ui/omnibox/omnibox_current_page_delegate_impl.cc

Index: chrome/browser/ui/omnibox/omnibox_current_page_delegate_impl.cc
diff --git a/chrome/browser/ui/omnibox/omnibox_current_page_delegate_impl.cc b/chrome/browser/ui/omnibox/omnibox_current_page_delegate_impl.cc
index 345a9e89428b3192d5a971c7dc900de93aa1ff02..5f95966053b12f86a8301e1001be806f8867dc1c 100644
--- a/chrome/browser/ui/omnibox/omnibox_current_page_delegate_impl.cc
+++ b/chrome/browser/ui/omnibox/omnibox_current_page_delegate_impl.cc
@@ -91,10 +91,24 @@ void OmniboxCurrentPageDelegateImpl::OnInputStateChanged() {
 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(