Remove the iOS QR Code scanner experiment code.

ios/chrome/browser/experimental_flags.mm

Index: ios/chrome/browser/experimental_flags.mm
diff --git a/ios/chrome/browser/experimental_flags.mm b/ios/chrome/browser/experimental_flags.mm
index 892a61629f70af296513627b6cbc7593e8bdf69f..4361aaf389af988a50ea5c2b48996994272eb35e 100644
--- a/ios/chrome/browser/experimental_flags.mm
+++ b/ios/chrome/browser/experimental_flags.mm
@@ -221,11 +221,6 @@ bool IsPhysicalWebEnabled() {
                           base::CompareCase::INSENSITIVE_ASCII);
 }
 
-bool IsQRCodeReaderEnabled() {
-  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
-  return !command_line->HasSwitch(switches::kDisableQRScanner);
-}
-
 bool IsReaderModeEnabled() {
   return base::CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kEnableReaderModeToolbarIcon);