Fixes alternating keyboard and mouse hot-tracking in menus

ui/views/controls/menu/menu_item_view.cc

 // Copyright (c) 2012 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 "ui/views/controls/menu/menu_item_view.h"
 
 #include <stddef.h>
 
 #include "base/i18n/case_conversion.h"
 #include "base/macros.h"
@@ skipping 529 matching lines @@
   } else {
     // Child views are laid out right aligned and given the full height. To
     // right align start with the last view and progress to the first.
     int x = width() - (use_right_margin_ ? item_right_margin_ : 0);
     for (int i = child_count() - 1; i >= 0; --i) {
       View* child = child_at(i);
       if (icon_view_ && (icon_view_ == child))
         continue;
       int width = child->GetPreferredSize().width();
       child->SetBounds(x - width, 0, width, height());
-      x -= width - kChildXPadding;
+      x -= width + kChildXPadding;

[varkha, 2016/02/26 22:07:10]

I think this is a typo that I came across while writing a test for hot-tracking.
The reason I think we have never noticed that is because we have container views
that host child buttons in app menu and those container views ensure proper
layout.
Consider line
https://code.google.com/p/chromium/codesearch#chromium/src/ui/views/controls/...
which is using padding correctly to add to the preferred width.

     }
     // Position |icon_view|.
     const MenuConfig& config = MenuConfig::instance();
     if (icon_view_) {
       icon_view_->SizeToPreferredSize();
       gfx::Size size = icon_view_->GetPreferredSize();
       int x = config.item_left_margin + left_icon_margin_ +
               (icon_area_width_ - size.width()) / 2;
       if (config.icons_in_label || type_ == CHECKBOX || type_ == RADIO)
         x = label_start_;
@@ skipping 520 matching lines @@
     } else {
       const Type& type = menu_item->GetType();
       if (type == CHECKBOX || type == RADIO)
         return true;
     }
   }
   return false;
 }
 
 }  // namespace views