Fall back to local page if online NTP fails to load.

chrome/browser/ui/search/instant_page.cc

Index: chrome/browser/ui/search/instant_page.cc
diff --git a/chrome/browser/ui/search/instant_page.cc b/chrome/browser/ui/search/instant_page.cc
index f1ae57f07de3e3e52d1f5be1f082167c0b2ae647..37d294b199c4387ed48f0659552c6171f1b6898e 100644
--- a/chrome/browser/ui/search/instant_page.cc
+++ b/chrome/browser/ui/search/instant_page.cc
@@ -7,7 +7,9 @@
 #include "base/utf_string_conversions.h"
 #include "chrome/common/render_messages.h"
 #include "chrome/common/url_constants.h"
+#include "content/public/browser/navigation_details.h"
 #include "content/public/browser/web_contents.h"
+#include "content/public/common/frame_navigate_params.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/font.h"
 
@@ -193,6 +195,27 @@ void InstantPage::DidCommitProvisionalLoadForFrame(
     delegate_->InstantPageAboutToNavigateMainFrame(contents(), url);
 }
 
+void InstantPage::DidNavigateMainFrame(
+    const content::LoadCommittedDetails& details,
+    const content::FrameNavigateParams& /* params */) {
+  // A 204 can be sent by the search provider as a lightweight signal
+  // to fall back to the local page, and we obviously want to fall back
+  // if we get any response code that indicates an error.
+  if (details.http_status_code == 204 || details.http_status_code >= 400)
+    delegate_->InstantPageLoadFailed(contents());
+}
+
+void InstantPage::DidFailProvisionalLoad(
+    int64 /* frame_id */,
+    bool is_main_frame,
+    const GURL& /* validated_url */,
+    int /* error_code */,
+    const string16& /* error_description */,
+    content::RenderViewHost* /* render_view_host */) {
+  if (is_main_frame)
+    delegate_->InstantPageLoadFailed(contents());
+}
+
 void InstantPage::OnSetSuggestions(
     int page_id,
     const std::vector<InstantSuggestion>& suggestions) {