- Electron version: 1.3.5
- Operating system: macOS/Windows

Alt-clicking a link is a default shortcut for downloading a file without a save prompt, and we make use of it in our app. But for links that end in a trailing slash, the resulting filename isn't consistent with the default file name in the save prompt.

The save prompt constructs a name from the word "download" and the extension for the mime type of the file, but the prompt-less savepath is just the domain name of the link. This leads to unusable files (e.g. with a .com file extension) being saved to the filesystem.

Here's my current workaround, but given the prompt does get a useful path, and Chrome behaves correctly, I imagine this might be straightforward to fix if you know where to look:

``` javascript
const mime = require('mime-types');
const _ = require('lodash');
const path = require('path');
const unusedFilename = require('unused-filename');

win.webContents.session.on('will-download', function (e, item, webContents) {
  if (item.getSavePath() && _.last(item.getURL()) === '/') {
      var savePath = unusedFilename.sync(path.format({
        dir: path.dirname(item.getSavePath()),
        name: 'download',
        ext: '.' + mime.extension(item.getMimeType())
      }));
      item.setSavePath(savePath);
    }
});
```

atom/browser/api/atom_api_web_contents.cc
if (!IsOffScreen())
    return false;
  const auto* osr_rwhv = static_cast<OffScreenRenderWidgetHostView*>(
      web_contents()->GetRenderWidgetHostView());
  return osr_rwhv && osr_rwhv->IsPainting();
}
void WebContents::SetFrameRate(int frame_rate) {
  if (!IsOffScreen())
    return;
  auto* osr_rwhv = static_cast<OffScreenRenderWidgetHostView*>(
      web_contents()->GetRenderWidgetHostView());
  if (osr_rwhv)
    osr_rwhv->SetFrameRate(frame_rate);
}
int WebContents::GetFrameRate() const {
  if (!IsOffScreen())
    return 0;
  const auto* osr_rwhv = static_cast<OffScreenRenderWidgetHostView*>(
      web_contents()->GetRenderWidgetHostView());
  return osr_rwhv ? osr_rwhv->GetFrameRate() : 0;
}
v8::Local<v8::Value> WebContents::GetWebPreferences(v8::Isolate* isolate) {
  WebContentsPreferences* web_preferences =
      WebContentsPreferences::FromWebContents(web_contents());
  return mate::ConvertToV8(isolate, *web_preferences->web_preferences());
}
v8::Local<v8::Value> WebContents::GetOwnerBrowserWindow() {