- 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/browser.h
BOUNCE_CRITICAL = 0,
    BOUNCE_INFORMATIONAL = 10,
  };
  int DockBounce(BounceType type);
  void DockCancelBounce(int request_id);
  
  void DockDownloadFinished(const std::string& filePath);
  
  void DockSetBadgeText(const std::string& label);
  std::string DockGetBadgeText();
  
  void DockHide();
  void DockShow();
  
  void DockSetMenu(AtomMenuModel* model);
  
  void DockSetIcon(const gfx::Image& image);
  
  LoginItemSettings GetLoginItemSettings();
  
  void SetLoginItemSettings(LoginItemSettings settings);
#endif  
#if defined(OS_WIN)
  struct UserTask {
    base::FilePath program;
    base::string16 arguments;