* Electron version: 1.7.6
* Operating system: macOS 10.12, Windows 10

### Expected behavior

Right clicking should open context menu in devtools

### Actual behavior

Right clicking does not open the context menu in devtools

### How to reproduce

- `open Electron.app --args --enable-mixed-sandbox`
- open devtools
- right click in the source tab for example
atom/renderer/atom_sandboxed_renderer_client.cc
mate::Dictionary global(isolate, isolate->GetCurrentContext()->Global());
  v8::Local<v8::Value> cache;
  if (!global.GetHidden(kModuleCacheKey, &cache)) {
    cache = v8::Object::New(isolate);
    global.SetHidden(kModuleCacheKey, cache);
  }
  return cache->ToObject();
}
v8::Local<v8::Value> GetBinding(v8::Isolate* isolate, v8::Local<v8::String> key,