[New Tab Page] Change the mechanism to intercept online NTP errors

chrome/browser/search/search.h

 // 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.
 
 #ifndef CHROME_BROWSER_SEARCH_SEARCH_H_
 #define CHROME_BROWSER_SEARCH_SEARCH_H_
 
 #include <string>
 #include <utility>
 #include <vector>
@@ skipping 12 matching lines @@
 class NavigationEntry;
 class WebContents;
 }
 
 namespace user_prefs {
 class PrefRegistrySyncable;
 }
 
 namespace chrome {
 
+// For reporting Cacheable NTP navigations.
+enum CacheableNTPLoad {
+  CACHEABLE_NTP_LOAD_FAILED = 0,
+  CACHEABLE_NTP_LOAD_SUCCEEDED = 1,
+  CACHEABLE_NTP_LOAD_MAX = 2
+};
+
 enum OptInState {
   // The user has not manually opted in/out of InstantExtended.
   INSTANT_EXTENDED_NOT_SET,
   // The user has opted-in to InstantExtended.
   INSTANT_EXTENDED_OPT_IN,
   // The user has opted-out of InstantExtended.
   INSTANT_EXTENDED_OPT_OUT,
   INSTANT_EXTENDED_OPT_IN_STATE_ENUM_COUNT,
 };
 
@@ skipping 210 matching lines @@
 
 // Returns true if 'use_search_path_for_instant' flag is set to true in field
 // trials to use an '/search' path in an alternate Instant search base page URL
 // for prefetching search results. This allows experimentation of Instant
 // search.
 bool ShouldUseSearchPathForInstant();
 
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_SEARCH_SEARCH_H_