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/net/internal_scheme_handler.h

@@ -8,7 +8,6 @@
 
 #include <string>
 #include "include/cef_scheme.h"
-#include "base/memory/scoped_ptr.h"
 #include "url/gurl.h"
 
 namespace scheme {
@@ -47,7 +46,7 @@ class InternalHandlerDelegate {
 // Create an internal scheme handler factory. The factory will take ownership of
 // |delegate|.
 CefRefPtr<CefSchemeHandlerFactory> CreateInternalHandlerFactory(
-    scoped_ptr<InternalHandlerDelegate> delegate);
+    std::unique_ptr<InternalHandlerDelegate> delegate);
 
 }  // namespace scheme