[Mac] Reverse tabs in RTL mode

chrome/browser/ui/cocoa/l10n_util.h

Index: chrome/browser/ui/cocoa/l10n_util.h
diff --git a/chrome/browser/ui/cocoa/l10n_util.h b/chrome/browser/ui/cocoa/l10n_util.h
index a0a29ecaa100e3230fc396a7eab63292e3cc7bb6..fcf68d99634379baa24d16970b50a7c17b9f5b6d 100644
--- a/chrome/browser/ui/cocoa/l10n_util.h
+++ b/chrome/browser/ui/cocoa/l10n_util.h
@@ -5,6 +5,7 @@
 #import <Cocoa/Cocoa.h>
 #include <stddef.h>
 
+#include "base/feature_list.h"
 #include "base/strings/string16.h"
 
 namespace cocoa_l10n_util {
@@ -33,6 +34,7 @@ NSString* ReplaceNSStringPlaceholders(NSString* formatString,
 // Generates a tooltip string for a given URL and title.
 NSString* TooltipForURLAndTitle(NSString* url, NSString* title);
 
+extern const base::Feature kExperimentalMacRTL;
 // Returns whether both:
 // 1) Experimental Mac RTL support is enabled via the ExperimentalMacRTL
 //    feature;