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/resource_util_win.cc

@@ -14,7 +14,7 @@ namespace client {
 namespace {
 
 bool LoadBinaryResource(int binaryId, DWORD& dwSize, LPBYTE& pBytes) {
-  HINSTANCE hInst = GetModuleHandle(NULL);
+  HINSTANCE hInst = GetModuleHandle(nullptr);
   HRSRC hRes =
       FindResource(hInst, MAKEINTRESOURCE(binaryId), MAKEINTRESOURCE(256));
   if (hRes) {