Various fixes related to the C++11/14 update (see issue #3140)

- Convert scoped_ptr to std::unique_ptr from <memory>
- Convert arraysize to base::size from include/base/cef_cxx17_backports.h
- Convert NULL to nullptr
- Include include/base/cef_callback.h instead of include/base/cef_bind.h
- Implicit conversion of CefRefPtr<T> or scoped_refptr<T> to T* is gone;
  use .get() instead

See the issue for additional details.

tests/shared/browser/main_message_loop.h

@@ -6,8 +6,9 @@
 #define CEF_TESTS_SHARED_BROWSER_MAIN_MESSAGE_LOOP_H_
 #pragma once
 
-#include "include/base/cef_bind.h"
-#include "include/base/cef_scoped_ptr.h"
+#include <memory>
+
+#include "include/base/cef_callback.h"
 #include "include/cef_task.h"
 
 #if defined(OS_WIN)
@@ -50,8 +51,8 @@ class MainMessageLoop {
   void PostClosure(const base::Closure& closure);
 
  protected:
-  // Only allow deletion via scoped_ptr.
-  friend struct base::DefaultDeleter<MainMessageLoop>;
+  // Only allow deletion via std::unique_ptr.
+  friend std::default_delete<MainMessageLoop>;
 
   MainMessageLoop();
   virtual ~MainMessageLoop();
@@ -97,7 +98,7 @@ struct DeleteOnMainThread {
       delete x;
     } else {
       client::MainMessageLoop::Get()->PostClosure(
-          base::Bind(&DeleteOnMainThread::Destruct<T>, x));
+          base::Bind(&DeleteOnMainThread::Destruct<T>, base::Unretained(x)));
     }
   }
 };