* Electron version: 1.8.2
* Operating system: macos 10.13.3

Reproducing repo: https://github.com/ibash/electron-webkit-app-drag

Demonstrates a bug where `-webkit-app-region: drag` causes a browser view in front of it to miss click events. Oddly - it does not prevent hover events.

Steps:
1. Clone https://github.com/ibash/electron-webkit-app-drag, `yarn install`, `yarn start`
2. Click "button1"
3. Click "button2"

Expected:

Clicking button1 or button2 pops up an alert: "button clicked!"

Actual:

Only clicking button2 pops up an alert: "button clicked!"

atom/browser/api/atom_api_browser_window.cc
auto* host = web_contents()->GetRenderViewHost();
  if (host)
    host->GetWidget()->RemoveInputEventObserver(this);
  api_web_contents_->DestroyWebContents(true );
  Observe(nullptr);
  RemoveFromWeakMap();
  window_->RemoveObserver(this);
  
  
  MarkDestroyed();
  Emit("closed");
  RemoveFromParentChildWindows();
  ResetBrowserView();
  
  base::ThreadTaskRunnerHandle::Get()->PostTask(
      FROM_HERE, GetDestroyClosure());
}
void BrowserWindow::OnWindowEndSession() {
  Emit("session-end");
}
void BrowserWindow::OnWindowBlur() {
  web_contents()->StoreFocus();
#if defined(OS_MACOSX)
  auto* rwhv = web_contents()->GetRenderWidgetHostView();
  if (rwhv)
    rwhv->SetActive(false);
#endif
  Emit("blur");
}
void BrowserWindow::OnWindowFocus() {