[Mac] Flip toolbar button images in RTL

chrome/browser/ui/cocoa/toolbar/toolbar_button_cocoa.mm

Index: chrome/browser/ui/cocoa/toolbar/toolbar_button_cocoa.mm
diff --git a/chrome/browser/ui/cocoa/toolbar/toolbar_button_cocoa.mm b/chrome/browser/ui/cocoa/toolbar/toolbar_button_cocoa.mm
index 6e7e612d22c24f5eed70b8c2316045b75d1b18aa..2640313df0a6c88c034a807b846f487b98bbaed1 100644
--- a/chrome/browser/ui/cocoa/toolbar/toolbar_button_cocoa.mm
+++ b/chrome/browser/ui/cocoa/toolbar/toolbar_button_cocoa.mm
@@ -207,12 +207,11 @@ const NSSize kMDButtonIconSize = NSMakeSize(16, 16);
 }
 
 - (const gfx::VectorIcon*)vectorIcon {
-  BOOL isRTL = cocoa_l10n_util::ShouldDoExperimentalRTLLayout();
   switch ([self viewID]) {
     case VIEW_ID_BACK_BUTTON:
-      return isRTL ? &ui::kForwardArrowIcon : &ui::kBackArrowIcon;
+      return &ui::kBackArrowIcon;
     case VIEW_ID_FORWARD_BUTTON:
-      return isRTL ? &ui::kBackArrowIcon : &ui::kForwardArrowIcon;
+      return &ui::kForwardArrowIcon;
     case VIEW_ID_HOME_BUTTON:
       return &kNavigateHomeIcon;
     case VIEW_ID_APP_MENU:
@@ -312,17 +311,21 @@ const NSSize kMDButtonIconSize = NSMakeSize(16, 16);
       normalIcon = [self browserToolsIconForFillColor:normalColor];
       disabledIcon = [self browserToolsIconForFillColor:disabledColor];
     } else {
+      BOOL isRTL = cocoa_l10n_util::ShouldDoExperimentalRTLLayout();
       normalIcon = NSImageFromImageSkia(
           gfx::CreateVectorIcon(*icon,
                                 kMDButtonIconSize.width,
                                 normalColor));
-
+      if (isRTL)
+        normalIcon = cocoa_l10n_util::FlippedImage(normalIcon);
       // The home button has no icon for its disabled state.
       if (icon != &kNavigateReloadIcon) {
         disabledIcon = NSImageFromImageSkia(
             gfx::CreateVectorIcon(*icon,
                                   kMDButtonIconSize.width,
                                   disabledColor));
+        if (isRTL)
+          disabledIcon = cocoa_l10n_util::FlippedImage(disabledIcon);
       }
     }
   }