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.

libcef/browser/browser_platform_delegate.h

@@ -356,7 +356,7 @@ class CefBrowserPlatformDelegate {
   virtual void StopFinding(bool clearSelection);
 
  protected:
-  // Allow deletion via scoped_ptr only.
+  // Allow deletion via std::unique_ptr only.
   friend std::default_delete<CefBrowserPlatformDelegate>;
 
   CefBrowserPlatformDelegate();

libcef/browser/file_dialog_runner.h

@@ -39,7 +39,7 @@ class CefFileDialogRunner {
                    RunFileChooserCallback callback) = 0;
 
  protected:
-  // Allow deletion via scoped_ptr only.
+  // Allow deletion via std::unique_ptr only.
   friend std::default_delete<CefFileDialogRunner>;
 
   CefFileDialogRunner() {}

libcef/browser/javascript_dialog_runner.h

@@ -30,7 +30,7 @@ class CefJavaScriptDialogRunner {
   virtual void Cancel() = 0;
 
  protected:
-  // Allow deletion via scoped_ptr only.
+  // Allow deletion via std::unique_ptr only.
   friend std::default_delete<CefJavaScriptDialogRunner>;
 
   CefJavaScriptDialogRunner() {}

libcef/browser/menu_runner.h

@@ -27,7 +27,7 @@ class CefMenuRunner {
   virtual bool FormatLabel(std::u16string& label) { return false; }
 
  protected:
-  // Allow deletion via scoped_ptr only.
+  // Allow deletion via std::unique_ptr only.
   friend std::default_delete<CefMenuRunner>;
 
   CefMenuRunner() {}

libcef/browser/osr/render_widget_host_view_osr.cc

@@ -1615,7 +1615,7 @@ void CefRenderWidgetHostViewOSR::CancelWidget() {
   if (render_widget_host_ && !is_destroyed_) {
     is_destroyed_ = true;
 
-    // Don't delete the RWHI manually while owned by a scoped_ptr in RVHI.
+    // Don't delete the RWHI manually while owned by a std::unique_ptr in RVHI.
     // This matches a CHECK() in RenderWidgetHostImpl::Destroy().
     const bool also_delete = !render_widget_host_->owner_delegate();