- Electron version: 0.37.6
- Operating system: Windows 10

In VSCode, in order to support screen readers while editing text, we set the contents of a `<textarea>` to the contents of the line and lines surrounding the cursor and we mirror the editor selection in the `<textarea>` via `setSelectionRange`.

Chromium is not the fastest when it comes to setting large amounts of text :) (such as > 10,000 characters) and basically stalls all the time. Apparently, Electron already has some knowledge about when a screen reader is attached to the main process window (in C++ code). Is it possible to expose this as a getter + event when it first happens in the `electron` API.

We could then maintain this costly `<textarea>` sync only when really needed.

atom/browser/api/atom_api_app.cc
content::WebContents* web_contents,
    int cert_error,
    const net::SSLInfo& ssl_info,
    const GURL& request_url,
    content::ResourceType resource_type,
    bool overridable,
    bool strict_enforcement,
    bool expired_previous_decision,
    const base::Callback<void(bool)>& callback,
    content::CertificateRequestResultType* request) {
  v8::Locker locker(isolate());
  v8::HandleScope handle_scope(isolate());
  bool prevent_default = Emit("certificate-error",
                              WebContents::CreateFrom(isolate(), web_contents),
                              request_url,
                              net::ErrorToString(cert_error),
                              ssl_info.cert,
                              callback);
  
  if (!prevent_default)
    *request = content::CERTIFICATE_REQUEST_RESULT_TYPE_DENY;
}
void App::SelectClientCertificate(