- Electron version: 1.2.0
- Operating system: Mac OS X - 10.11.5

I upgraded from 1.1.1 to 1.2.0. 1.2.0 breaks on the following `index.html`:

``` html
<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="utf-8">
        <script>
            console.log(process.env.NODE_ENV)
        </script>
    </head>
    <body>
        <div id="app-container"></div>
    </body>
</html>
```

Error:

```
Uncaught ReferenceError: process is not defined
```

atom/renderer/atom_renderer_client.cc
new printing::PrintWebViewHelper(render_view);
  new AtomRenderViewObserver(render_view, this);
  blink::WebFrameWidget* web_frame_widget = render_view->GetWebFrameWidget();
  if (!web_frame_widget)
    return;
  base::CommandLine* cmd = base::CommandLine::ForCurrentProcess();
  if (cmd->HasSwitch(switches::kGuestInstanceID)) {  
    web_frame_widget->setBaseBackgroundColor(SK_ColorTRANSPARENT);
  } else {  
    
    std::string name = cmd->GetSwitchValueASCII(switches::kBackgroundColor);
    
    SkColor color = name.empty() ? SK_ColorWHITE : ParseHexColor(name);
    web_frame_widget->setBaseBackgroundColor(color);
  }
}
void AtomRendererClient::RunScriptsAtDocumentStart(
    content::RenderFrame* render_frame) {
  
  render_frame->GetWebFrame()->executeScript(
      blink::WebScriptSource("void 0"));
  
  node::Environment* env = node_bindings_->uv_env();
  if (env) {
    v8::HandleScope handle_scope(env->isolate());
    mate::EmitEvent(env->isolate(), env->process_object(), "document-start");
  }
}
void AtomRendererClient::RunScriptsAtDocumentEnd(