Removes the IsReadingListEnabled flags

ios/chrome/browser/experimental_flags.h

 // Copyright 2014 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 IOS_CHROME_BROWSER_EXPERIMENTAL_FLAGS_H_
 #define IOS_CHROME_BROWSER_EXPERIMENTAL_FLAGS_H_
 
 #include <string>
 
 // This file can be empty. Its purpose is to contain the relatively short lived
@@ skipping 64 matching lines @@
 
 // Whether the Payment Request API is enabled or not.
 bool IsPaymentRequestEnabled();
 
 // Whether the Physical Web feature is enabled.
 bool IsPhysicalWebEnabled();
 
 // Whether reader mode is enabled.
 bool IsReaderModeEnabled();
 
-// Whether the reading list is enabled.
-bool IsReadingListEnabled();
-
 // Whether the Sign In Flow via SFSafariViewController is enabled.
 bool IsSafariVCSignInEnabled();
 
 // Whether startup crash is enabled.
 bool IsStartupCrashEnabled();
 
 // Whether or not the tab strip scrolls new tabs to be visible.
 bool IsTabStripAutoScrollNewTabsEnabled();
 
 // Whether viewing and copying passwords is enabled.
 bool IsViewCopyPasswordsEnabled();
 
 // Whether password generation fields are determined using local heuristics
 // only.
 bool UseOnlyLocalHeuristicsForPasswordGeneration();
 
 // Whether the Suggestions UI is enabled.
 bool IsSuggestionsUIEnabled();
 
 }  // namespace experimental_flags
 
 #endif  // IOS_CHROME_BROWSER_EXPERIMENTAL_FLAGS_H_