Revert 244407 "InstantExtended: remove dead code related to the ..."

trunk/src/chrome/browser/ui/search/instant_controller.cc

Index: trunk/src/chrome/browser/ui/search/instant_controller.cc
===================================================================
--- trunk/src/chrome/browser/ui/search/instant_controller.cc	(revision 244428)
+++ trunk/src/chrome/browser/ui/search/instant_controller.cc	(working copy)
@@ -117,6 +117,29 @@
   }
 }
 
+void InstantController::InstantPageLoadFailed(content::WebContents* contents) {
+  DCHECK(IsContentsFrom(instant_tab(), contents));
+
+  // Verify we're not already on a local page and that the URL precisely
+  // equals the instant_url (minus the query params, as those will be filled
+  // in by template values).  This check is necessary to make sure we don't
+  // inadvertently redirect to the local NTP if someone, say, reloads a SRP
+  // while offline, as a committed results page still counts as an instant
+  // url.  We also check to make sure there's no forward history, as if
+  // someone hits the back button a lot when offline and returns to a NTP
+  // we don't want to redirect and nuke their forward history stack.
+  const GURL& current_url = contents->GetURL();
+  GURL instant_url = chrome::GetInstantURL(profile(),
+                                           chrome::kDisableStartMargin, false);
+  if (instant_tab_->IsLocal() ||
+      !search::MatchesOriginAndPath(instant_url, current_url) ||
+      !current_url.ref().empty() ||
+      contents->GetController().CanGoForward())
+    return;
+  LOG_INSTANT_DEBUG_EVENT(this, "InstantPageLoadFailed: instant_tab");
+  RedirectToLocalNTP(contents);
+}
+
 bool InstantController::SubmitQuery(const base::string16& search_terms) {
   if (instant_tab_ && instant_tab_->supports_instant() &&
       search_mode_.is_origin_search()) {
@@ -273,6 +296,17 @@
       omnibox_focus_state_ == OMNIBOX_FOCUS_VISIBLE;
 }
 
+void InstantController::RedirectToLocalNTP(content::WebContents* contents) {
+  contents->GetController().LoadURL(
+      GURL(chrome::kChromeSearchLocalNtpUrl),
+      content::Referrer(),
+      content::PAGE_TRANSITION_SERVER_REDIRECT,
+      std::string());  // No extra headers.
+  // TODO(dcblack): Remove extraneous history entry caused by 404s.
+  // Note that the base case of a 204 being returned doesn't push a history
+  // entry.
+}
+
 InstantService* InstantController::GetInstantService() const {
   return InstantServiceFactory::GetForProfile(profile());
 }