[ios] Experimental flag for Pending Index Navigations.

ios/chrome/browser/experimental_flags.mm

 // Copyright 2015 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.
 
 // This file can be empty. Its purpose is to contain the relatively short lived
 // definitions required for experimental flags.
 
 #include "ios/chrome/browser/experimental_flags.h"
 
 #include <dispatch/dispatch.h>
@@ skipping 11 matching lines @@
 
 namespace {
 NSString* const kEnableAlertOnBackgroundUpload =
     @"EnableAlertsOnBackgroundUpload";
 NSString* const kEnableViewCopyPasswords = @"EnableViewCopyPasswords";
 NSString* const kHeuristicsForPasswordGeneration =
     @"HeuristicsForPasswordGeneration";
 NSString* const kEnableReadingList = @"EnableReadingList";
 NSString* const kEnableNewClearBrowsingDataUI = @"EnableNewClearBrowsingDataUI";
 NSString* const kMDMIntegrationDisabled = @"MDMIntegrationDisabled";
+NSString* const kPendingIndexNavigationEnabled =
+    @"PendingIndexNavigationEnabled";
 }  // namespace
 
 namespace experimental_flags {
 
 bool IsAlertOnBackgroundUploadEnabled() {
   return [[NSUserDefaults standardUserDefaults]
       boolForKey:kEnableAlertOnBackgroundUpload];
 }
 
 bool IsLRUSnapshotCacheEnabled() {
@@ skipping 131 matching lines @@
 bool IsSpotlightActionsEnabled() {
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
   return !command_line->HasSwitch(switches::kDisableSpotlightActions);
 }
 
 bool IsMDMIntegrationEnabled() {
   return ![[NSUserDefaults standardUserDefaults]
       boolForKey:kMDMIntegrationDisabled];
 }
 
+bool IsPendingIndexNavigationEnabled() {
+  return [[NSUserDefaults standardUserDefaults]
+      boolForKey:kPendingIndexNavigationEnabled];
+}
+
 }  // namespace experimental_flags