MacViews: fix bubble direction in RTL.

ui/views/style/platform_style_mac.mm

Index: ui/views/style/platform_style_mac.mm
diff --git a/ui/views/style/platform_style_mac.mm b/ui/views/style/platform_style_mac.mm
index 8d4ef5d8e77f8123034124c99c8a26997e8f5d9d..0b983bb5b5dc0a4b7e5070e33fd6b685d6497075 100644
--- a/ui/views/style/platform_style_mac.mm
+++ b/ui/views/style/platform_style_mac.mm
@@ -6,6 +6,7 @@
 
 #include "base/memory/ptr_util.h"
 #include "ui/base/resource/resource_bundle.h"
+#include "ui/base/ui_features.h"
 #include "ui/gfx/color_utils.h"
 #include "ui/gfx/paint_vector_icon.h"
 #include "ui/gfx/vector_icons_public.h"
@@ -27,6 +28,12 @@ const bool PlatformStyle::kTreeViewHasFocusRing = true;
 const bool PlatformStyle::kTreeViewSelectionPaintsEntireRow = true;
 const bool PlatformStyle::kUseRipples = false;
 
+// On Mac, the Cocoa browser window does not flip its UI in RTL (e.g. bookmark
+// star remains on the right, padlock on the left). So bubbles should open in
+// the same direction as in LTR by default, unless the entire browser is views.
+const bool PlatformStyle::kMirrorBubbleArrowInRTLByDefault =
+    BUILDFLAG(MAC_VIEWS_BROWSER);
+
 const CustomButton::NotifyAction PlatformStyle::kMenuNotifyActivationAction =
     CustomButton::NOTIFY_ON_PRESS;