FATAL assertion in thread_restrictions.cc

[magreenblatt]

But in addition to that, I think I initially had the app configured with the default MP mode and the CefRenderProcessHandler::OnContextCreated was not getting called

OnContextCreated is executed in the renderer process. You need to pass a CefApp instance to CefExecuteProcess and implement CefApp::GetRenderProcessHandler.

[Czarek]

Itai Bar-Haim answered correctly to your question on stackoverflow. OnContextCreated runs in the renderer process and your debugger was attached only to the main browser process, thus your breakpoint didn't work.