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/cefclient/browser/browser_window_osr_mac.h

@@ -91,7 +91,7 @@ class BrowserWindowOsrMac : public BrowserWindow,
   void UpdateAccessibilityLocation(CefRefPtr<CefValue> value) override;
 
  private:
-  scoped_ptr<BrowserWindowOsrMacImpl> impl_;
+  std::unique_ptr<BrowserWindowOsrMacImpl> impl_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserWindowOsrMac);