Steps to reproduce the problem:
Load a remote DevTools front-end in a webview (same Electron version on both ends)

What is the expected behavior?
Remote DevTools is opened in the webview

What went wrong?
"Uncaught TypeError: Cannot read property 'extensions' of undefined".
At this point, it tries to access window.runtime.extensions("settings").
See screenshot.

Did this work before? Yes 51.0.2704.63

Chrome version: 52.0.2743.82
OS Version: OS X 10.11.4

Worked fine until Electron 1.2.0 (Chromium 51.0.2704.63) with the disablewebsecurity attribute set. Broken on 1.2.1.
Current chromium version (1.3.0): 52.0.2743.82

![screen shot 2016-07-25 at 5 36 13 pm](https://cloud.githubusercontent.com/assets/1028286/17125639/1a265cce-52aa-11e6-8413-2d75c642dbb2.png)

atom/common/node_bindings.cc
embed_closed_ = true;
  uv_sem_post(&embed_sem_);
  WakeupEmbedThread();
  
  uv_thread_join(&embed_thread_);
  
  uv_sem_destroy(&embed_sem_);
}
void NodeBindings::Initialize() {
  
  node::g_standalone_mode = is_browser_;
  node::g_upstream_node_mode = false;
#if defined(OS_LINUX)
  
  if (!is_browser_)
    AtomCommandLine::InitializeFromCommandLine();
#endif
  
  
  node::Init(nullptr, nullptr, nullptr, nullptr);
#if defined(OS_WIN)
  
  
  std::unique_ptr<base::Environment> env(base::Environment::Create());
  if (env->HasVar("ELECTRON_DEFAULT_ERROR_MODE"))
    SetErrorMode(0);
#endif
}
node::Environment* NodeBindings::CreateEnvironment(