Add ScopedMacRTL class for Cocoa browser RTL testing

chrome/browser/ui/cocoa/tabs/tab_controller.mm

Index: chrome/browser/ui/cocoa/tabs/tab_controller.mm
diff --git a/chrome/browser/ui/cocoa/tabs/tab_controller.mm b/chrome/browser/ui/cocoa/tabs/tab_controller.mm
index 240d109a1015dbd751eaa87b74e9ce2841d969b1..f3824aa072faee731e325dd2e9ad12c2e22cf65c 100644
--- a/chrome/browser/ui/cocoa/tabs/tab_controller.mm
+++ b/chrome/browser/ui/cocoa/tabs/tab_controller.mm
@@ -11,7 +11,6 @@
 #include "base/mac/bundle_locations.h"
 #import "chrome/browser/themes/theme_properties.h"
 #import "chrome/browser/themes/theme_service.h"
-#include "chrome/browser/ui/cocoa/l10n_util.h"
 #import "chrome/browser/ui/cocoa/sprite_view.h"
 #import "chrome/browser/ui/cocoa/tabs/alert_indicator_button_cocoa.h"
 #import "chrome/browser/ui/cocoa/tabs/tab_controller_target.h"
@@ -20,6 +19,7 @@
 #include "content/public/browser/user_metrics.h"
 #import "extensions/common/extension.h"
 #import "ui/base/cocoa/menu_controller.h"
+#import "ui/base/cocoa/rtl_feature.h"
 #include "ui/base/material_design/material_design_controller.h"
 
 @implementation TabController
@@ -93,7 +93,7 @@ static const CGFloat kTabElementYOrigin = 6;
 
 - (id)init {
   if ((self = [super init])) {
-    BOOL isRTL = cocoa_l10n_util::ShouldDoExperimentalRTLLayout();
+    BOOL isRTL = ui::ShouldDoExperimentalRTLLayout();
     // Icon.
     const CGFloat iconOrigin =
         isRTL ? kInitialTabWidth - kTabLeadingPadding - kIconSize
@@ -345,7 +345,7 @@ static const CGFloat kTabElementYOrigin = 6;
   if (image == nil) {
     [self setIconView:nil];
   } else {
-    BOOL isRTL = cocoa_l10n_util::ShouldDoExperimentalRTLLayout();
+    BOOL isRTL = ui::ShouldDoExperimentalRTLLayout();
     if (iconView_.get() == nil) {
       base::scoped_nsobject<SpriteView> iconView([[SpriteView alloc] init]);
       [iconView setAutoresizingMask:isRTL
@@ -398,7 +398,7 @@ static const CGFloat kTabElementYOrigin = 6;
 
   [alertIndicatorButton_ setHidden:!newShowAlertIndicator];
 
-  BOOL isRTL = cocoa_l10n_util::ShouldDoExperimentalRTLLayout();
+  BOOL isRTL = ui::ShouldDoExperimentalRTLLayout();
 
   if (newShowAlertIndicator) {
     NSRect newFrame = [alertIndicatorButton_ frame];