Revert of Enable RL by default

ios/chrome/browser/about_flags.mm

 // 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.
 
 // Implementation of about_flags for iOS that sets flags based on experimental
 // settings.
 
 #include "ios/chrome/browser/about_flags.h"
 
 #include <stddef.h>
@@ skipping 216 matching lines @@
 
   // Populate command line flag for the Payment Request API.
   NSString* enable_payment_request =
       [defaults stringForKey:@"EnablePaymentRequest"];
   if ([enable_payment_request isEqualToString:@"Enabled"]) {
     command_line->AppendSwitch(switches::kEnablePaymentRequest);
   } else if ([enable_payment_request isEqualToString:@"Disabled"]) {
     command_line->AppendSwitch(switches::kDisablePaymentRequest);
   }
 
+  // Populate command line flags from Reading List.
+  if ([defaults boolForKey:@"EnableReadingList"]) {
+    command_line->AppendSwitch(reading_list::switches::kEnableReadingList);
+  } else {
+    command_line->AppendSwitch(reading_list::switches::kDisableReadingList);
+  }
+
   // Populate command line flag for Spotlight Actions.
   if ([defaults boolForKey:@"DisableSpotlightActions"]) {
     command_line->AppendSwitch(switches::kDisableSpotlightActions);
   }
 
   // Populate command line flag for the Rename "Save Image" to "Download Image"
   // experiment.
   NSString* enableDownloadRenaming =
       [defaults stringForKey:@"EnableDownloadRenaming"];
   if ([enableDownloadRenaming isEqualToString:@"Enabled"]) {
@@ skipping 87 matching lines @@
 }
 
 namespace testing {
 
 const flags_ui::FeatureEntry* GetFeatureEntries(size_t* count) {
   *count = arraysize(kFeatureEntries);
   return kFeatureEntries;
 }
 
 }  // namespace testing