- 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.h
}
namespace atom {
namespace api {
class App : public AtomBrowserClient::Delegate,
            public mate::EventEmitter<App>,
            public BrowserObserver,
            public content::GpuDataManagerObserver {
 public:
  static mate::Handle<App> Create(v8::Isolate* isolate);
  static void BuildPrototype(v8::Isolate* isolate,
                             v8::Local<v8::ObjectTemplate> prototype);
  
  void OnCreateWindow(const GURL& target_url,
                      const std::string& frame_name,
                      WindowOpenDisposition disposition,
                      int render_process_id,
                      int render_frame_id);
#if defined(USE_NSS_CERTS)
  void OnCertificateManagerModelCreated(
      std::unique_ptr<base::DictionaryValue> options,
      const net::CompletionCallback& callback,
      std::unique_ptr<CertificateManagerModel> model);
#endif
 protected:
  explicit App(v8::Isolate* isolate);
  ~App() override;
  
  void OnBeforeQuit(bool* prevent_default) override;
  void OnWillQuit(bool* prevent_default) override;