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

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

 // Copyright 2012 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/search/instant_controller.h"
 
 #include "base/prefs/pref_service.h"
 #include "base/strings/stringprintf.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/content_settings/content_settings_provider.h"
@@ skipping 99 matching lines @@
   } else {
     if (chrome::ShouldPrefetchSearchResults()) {
       InstantSearchPrerenderer* prerenderer =
           InstantSearchPrerenderer::GetForProfile(profile());
       if (prerenderer)
         prerenderer->Prerender(suggestion);
     }
   }
 }
 
+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()) {
     // Use |instant_tab_| to run the query if we're already on a search results
     // page. (NOTE: in particular, we do not send the query to NTPs.)
     SearchTabHelper::FromWebContents(instant_tab_->contents())->Submit(
         search_terms);
     instant_tab_->contents()->GetView()->Focus();
     EnsureSearchTermsAreSet(instant_tab_->contents(), search_terms);
     return true;
@@ skipping 136 matching lines @@
                                          omnibox_focus_change_reason_);
     instant_tab_->sender()->SetInputInProgress(IsInputInProgress());
   }
 }
 
 bool InstantController::IsInputInProgress() const {
   return !search_mode_.is_ntp() &&
       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());
 }