Add finch flag for rendering a recently closed link on the local ntp.

chrome/browser/search/search.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/search/search.h"
 
 #include "base/command_line.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "base/prefs/pref_service.h"
@@ skipping 50 matching lines @@
 
 const char kInstantExtendedActivationName[] = "instant";
 const InstantExtendedDefault kInstantExtendedActivationDefault =
     INSTANT_DEFAULT_ON;
 
 const char kLocalOnlyFlagName[] = "local_only";
 
 // Key for specifying remote NTP behavior trials.
 const char kUseRemoteNTPOnStartupFlagName[] = "use_remote_ntp_on_startup";
 
+// Key for showing the recent tabs link on the local NTP.
+const char kRecentTabsOnNTPFlagName[] = "show_recent_tabs";
+
 // Constants for the field trial name and group prefix.
 const char kInstantExtendedFieldTrialName[] = "InstantExtended";
 const char kGroupNumberPrefix[] = "Group";
 
 // If the field trial's group name ends with this string its configuration will
 // be ignored and Instant Extended will not be enabled by default.
 const char kDisablingSuffix[] = "DISABLED";
 
 // Remember if we reported metrics about opt-in/out state.
 bool instant_extended_opt_in_state_gate = false;
@@ skipping 428 matching lines @@
   FieldTrialFlags flags;
   if (GetFieldTrialInfo(
           base::FieldTrialList::FindFullName(kInstantExtendedFieldTrialName),
           &flags, NULL)) {
     return GetBoolValueForFlagWithDefault(kUseRemoteNTPOnStartupFlagName, false,
                                           flags);
   }
   return false;
 }
 
+bool ShouldShowRecentTabsOnNTP() {
+  FieldTrialFlags flags;
+  if (GetFieldTrialInfo(
+          base::FieldTrialList::FindFullName(kInstantExtendedFieldTrialName),
+          &flags, NULL)) {
+    return GetBoolValueForFlagWithDefault(
+        kRecentTabsOnNTPFlagName, false, flags);
+  }
+
+  return false;
+}
+
 bool MatchesOriginAndPath(const GURL& my_url, const GURL& other_url) {
   return MatchesOrigin(my_url, other_url) && my_url.path() == other_url.path();
 }
 
 GURL GetPrivilegedURLForInstant(const GURL& url, Profile* profile) {
   CHECK(ShouldAssignURLToInstantRenderer(url, profile))
       << "Error granting Instant access.";
 
   if (IsPrivilegedURLForInstant(url))
     return url;
@@ skipping 141 matching lines @@
   return instant_url.is_valid() &&
          (!IsInstantExtendedAPIEnabled() ||
           template_url->HasSearchTermsReplacementKey(instant_url));
 }
 
 void ResetInstantExtendedOptInStateGateForTest() {
   instant_extended_opt_in_state_gate = false;
 }
 
 }  // namespace chrome