### Issue Details

* **Electron Version:**
  * 3.0.x, 4.0.x, 5.0.x, 6.0.x
* **Operating System:**
  * macOS 10.14.5
* **Last Known Working Electron version:**
  * 2.0.x

### Expected Behavior
`BrowserWindow.on('swipe')` fires when doing a 3-finger swipe gesture.

### Actual Behavior
`BrowserWindow.on('swipe')` does not fire.

shell/browser/api/atom_api_browser_window.cc
if (api_web_contents_->IsOffScreen())
    BlurWebView();
  else
    TopLevelWindow::Blur();
}
void BrowserWindow::SetBackgroundColor(const std::string& color_name) {
  TopLevelWindow::SetBackgroundColor(color_name);
  auto* view = web_contents()->GetRenderWidgetHostView();
  if (view)
    view->SetBackgroundColor(ParseHexColor(color_name));
}
void BrowserWindow::SetBrowserView(v8::Local<v8::Value> value) {
  TopLevelWindow::ResetBrowserViews();
  TopLevelWindow::AddBrowserView(value);
#if defined(OS_MACOSX)
  UpdateDraggableRegions(draggable_regions_);
#endif
}
void BrowserWindow::AddBrowserView(v8::Local<v8::Value> value) {
  TopLevelWindow::AddBrowserView(value);
#if defined(OS_MACOSX)
  UpdateDraggableRegions(draggable_regions_);
#endif
}
void BrowserWindow::RemoveBrowserView(v8::Local<v8::Value> value) {