Implement local NTP for fallback.

chrome/browser/search/search.cc

Index: chrome/browser/search/search.cc
diff --git a/chrome/browser/search/search.cc b/chrome/browser/search/search.cc
index 438533603a8297e46ab6242fb98ccc8504246169..b6832a480baae558e1b780b911dc63ecf1964d45 100644
--- a/chrome/browser/search/search.cc
+++ b/chrome/browser/search/search.cc
@@ -310,7 +310,8 @@ bool NavEntryIsInstantNTP(const content::WebContents* contents,
   Profile* profile = Profile::FromBrowserContext(contents->GetBrowserContext());
   return IsInstantExtendedAPIEnabled() &&
          IsRenderedInInstantProcess(contents, profile) &&
-         IsInstantURL(entry->GetVirtualURL(), profile) &&
+         (IsInstantURL(entry->GetVirtualURL(), profile) ||
+          entry->GetVirtualURL() == GURL(chrome::kChromeSearchLocalNTPURL)) &&
          GetSearchTermsImpl(contents, entry).empty();
 }
 
@@ -320,7 +321,8 @@ bool ShouldAssignURLToInstantRenderer(const GURL& url, Profile* profile) {
          (url.SchemeIs(chrome::kChromeSearchScheme) ||
           IsInstantURL(url, profile) ||
           (IsInstantExtendedAPIEnabled() &&
-           url == GURL(chrome::kChromeSearchLocalOmniboxPopupURL)));
+          (url == GURL(chrome::kChromeSearchLocalNTPURL) ||

[samarth, 2013/03/19 02:35:53]

Actually these two checks are now redundant given the check for
kChromeSearchScheme above.  You can just remove then (and make sure the tests
still pass).

[jeremycho, 2013/03/19 03:30:35]

Done.

+           url == GURL(chrome::kChromeSearchLocalOmniboxPopupURL))));
 }
 
 void RegisterUserPrefs(PrefRegistrySyncable* registry) {