Update to Chromium revision 6e53600d (#386251)

- Remove |accept_lang| parameter from CefJSDialogHandler::OnJSDialog
  and CefFormatUrlForSecurityDisplay (see https://crbug.com/336973#c36).
- Remove remaining NPAPI-related code including functions from
  cef_web_plugin.h (see https://crbug.com/493212#c55).
- Mac: 10.7+ deployment target is now required for client applications.
- Mac: Remove CefBrowserHost::SetWindowVisibility (issue #1375). No
  replacement is required for windowed rendering. Use WasHidden for
  off-screen rendering.
- Windows: Visual Studio 2015 Update 2 is now required when building
  CEF/Chromium.

libcef/browser/native/native_menu_win.h

@@ -11,7 +11,6 @@
 
 #include "base/macros.h"
 #include "base/compiler_specific.h"
-#include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "base/strings/string16.h"
@@ -124,7 +123,7 @@ class NativeMenuWin : public MenuWrapper {
   // The window that receives notifications from the menu.
   class MenuHostWindow;
   friend MenuHostWindow;
-  scoped_ptr<MenuHostWindow> host_window_;
+  std::unique_ptr<MenuHostWindow> host_window_;
 
   // The HWND this menu is the system menu for, or NULL if the menu is not a
   // system menu.