Fix separator positioning in app menu dropdown in RTL.

chrome/browser/ui/views/toolbar/app_menu.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/views/toolbar/app_menu.h"
 
 #include <stdint.h>
 
 #include <algorithm>
 #include <cmath>
@@ skipping 140 matching lines @@
 
   explicit InMenuButtonBackground(ButtonType type) : type_(type) {}
 
   // Overridden from views::Background.
   void Paint(gfx::Canvas* canvas, View* view) const override {
     CustomButton* button = CustomButton::AsCustomButton(view);
     views::Button::ButtonState state =
         button ? button->state() : views::Button::STATE_NORMAL;
     int h = view->height();
 
-    // Draw leading border where needed. This is along the left edge unless the
-    // layout is RTL and the button isn't mirroring itself.
+    // Draw leading border if desired.
     gfx::Rect bounds(view->GetLocalBounds());
     if (type_ == LEADING_BORDER) {
+      // We need to flip the canvas for RTL iff the button is not auto-flipping
+      // already, so we end up flipping exactly once.
       gfx::ScopedRTLFlipCanvas scoped_canvas(
-          canvas, view->width(), view->flip_canvas_on_paint_for_rtl_ui());
+          canvas, view->width(), !view->flip_canvas_on_paint_for_rtl_ui());
       canvas->FillRect(gfx::Rect(0, 0, 1, h),
                        BorderColor(view, views::Button::STATE_NORMAL));
       bounds.Inset(gfx::Insets(0, 1, 0, 0));
     }
 
     // Fill in background for state.
     bounds.set_x(view->GetMirroredXForRect(bounds));
     DrawBackground(canvas, view, bounds, state);
   }
 
@@ skipping 1056 matching lines @@
                                 0,
                                 BookmarkMenuDelegate::SHOW_PERMANENT_FOLDERS,
                                 BOOKMARK_LAUNCH_LOCATION_APP_MENU);
 }
 
 int AppMenu::ModelIndexFromCommandId(int command_id) const {
   CommandIDToEntry::const_iterator ix = command_id_to_entry_.find(command_id);
   DCHECK(ix != command_id_to_entry_.end());
   return ix->second.second;
 }