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

chrome/browser/ui/search/instant_tab.cc

Index: chrome/browser/ui/search/instant_tab.cc
diff --git a/chrome/browser/ui/search/instant_tab.cc b/chrome/browser/ui/search/instant_tab.cc
index 0d1ab82076d4b4919cc98004016fc8ddd0c19ffc..327fbe0413fb0578ff098959385542576cd57002 100644
--- a/chrome/browser/ui/search/instant_tab.cc
+++ b/chrome/browser/ui/search/instant_tab.cc
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/search/instant_tab.h"
+#include "content/public/browser/web_contents.h"
 
 InstantTab::InstantTab(InstantPage::Delegate* delegate)
     : InstantPage(delegate, "") {
@@ -13,7 +14,12 @@ InstantTab::~InstantTab() {
 
 void InstantTab::Init(content::WebContents* contents) {
   SetContents(contents);
-  DetermineIfPageSupportsInstant();
+  if (!contents->IsLoading())

[samarth, 2013/05/02 21:57:18]

Reading
https://code.google.com/p/chromium/codesearch#chromium/src/content/public/bro...,
this check isn't quite right.

I think IsLoading will return true even if the page has fired onLoad, and then
is fetching a new resource. So if you switch tabs to a search page in this
state, we'll never register Instant support.

You need a better check that corresponds to the main frame still loading. Or if
you don't need it for your change, just leave it out.

[David Black, 2013/05/02 23:30:01]

Ah, good point.  IsWaitingForResponse seems much more like what we want here. 
Switched to that.

+    DetermineIfPageSupportsInstant();
+}
+
+bool InstantTab::ShouldProcessAboutToNavigateMainFrame() {
+  return true;
 }
 
 bool InstantTab::ShouldProcessSetSuggestions() {