Reland of Enable RL by default

ios/chrome/browser/about_flags.mm

Index: ios/chrome/browser/about_flags.mm
diff --git a/ios/chrome/browser/about_flags.mm b/ios/chrome/browser/about_flags.mm
index 4fbfd94f8c094bd904a8897c74c8dbf4201b0ae3..c810392229cd9d0043844e756872578f88affaee 100644
--- a/ios/chrome/browser/about_flags.mm
+++ b/ios/chrome/browser/about_flags.mm
@@ -234,13 +234,6 @@ void AppendSwitchesFromExperimentalSettings(base::CommandLine* command_line) {
     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);