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* Electron version: 1.6.1
* Operating system: macOS

### Expected behavior

navigator.geolocation.getCurrentPosition runs in background

### Actual behavior

the entire UI is frozen

### How to reproduce

```js
    navigator.geolocation.getCurrentPosition((pos) => {
      console.log('POS: ' + pos);
    }, (err) => {
      console.log('Geolocation error: ', err);
    }, {enableHighAccuracy: false});
```
atom/browser/common_web_contents_delegate.cc
const base::FilePath& file_system_path) {
  if (!web_contents_)
    return;
  std::string path = file_system_path.AsUTF8Unsafe();
  storage::IsolatedContext::GetInstance()->
      RevokeFileSystemByPath(file_system_path);
  auto pref_service = GetPrefService(GetDevToolsWebContents());
  DictionaryPrefUpdate update(pref_service, prefs::kDevToolsFileSystemPaths);
  update.Get()->RemoveWithoutPathExpansion(path, nullptr);
  base::StringValue file_system_path_value(path);
  web_contents_->CallClientFunction("DevToolsAPI.fileSystemRemoved",
                                    &file_system_path_value,
                                    nullptr, nullptr);
}
void CommonWebContentsDelegate::DevToolsIndexPath(