It doesn't look very good for "native" apps to overscroll when scrolling. Would be nice to have a BrowserWindow option to disable overscroll

![untitled12](https://cloud.githubusercontent.com/assets/170270/15033357/fc36e32e-1293-11e6-8cdc-6c17b0f504dd.gif)
## 
- Electron version: 0.37.8
- Operating system: OS X 10.11.4

atom/renderer/atom_renderer_client.cc
content::RenderFrame* render_frame) {
  new PepperHelper(render_frame);
  
  blink::WebSecurityPolicy::registerURLSchemeAsAllowingServiceWorkers("file");
  
  if (!render_frame->IsMainFrame())
    return;
  new AtomRenderFrameObserver(render_frame, this);
}
void AtomRendererClient::RenderViewCreated(content::RenderView* render_view) {
  base::CommandLine* cmd = base::CommandLine::ForCurrentProcess();
  if (cmd->HasSwitch(switches::kGuestInstanceID)) {  
    
    render_view->GetWebView()->setBaseBackgroundColor(SK_ColorTRANSPARENT);
  } else {  
    
    std::string name = cmd->GetSwitchValueASCII(switches::kBackgroundColor);
    
    SkColor color = name.empty() ? SK_ColorWHITE : ParseHexColor(name);
    render_view->GetWebView()->setBaseBackgroundColor(color);
  }
  new printing::PrintWebViewHelper(render_view);
  new AtomRenderViewObserver(render_view, this);
}
blink::WebSpeechSynthesizer* AtomRendererClient::OverrideSpeechSynthesizer(