- 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
#include "atom/common/native_mate_converters/net_converter.h"
#include "atom/common/native_mate_converters/value_converter.h"
#include "atom/common/node_includes.h"
#include "atom/common/options_switches.h"
#include "base/command_line.h"
#include "base/environment.h"
#include "base/files/file_path.h"
#include "base/files/file_util.h"
#include "base/path_service.h"
#include "base/strings/string_util.h"
#include "brightray/browser/brightray_paths.h"
#include "chrome/common/chrome_paths.h"
#include "content/public/browser/client_certificate_delegate.h"
#include "content/public/browser/gpu_data_manager.h"
#include "content/public/browser/render_frame_host.h"
#include "content/public/common/content_switches.h"
#include "native_mate/dictionary.h"
#include "native_mate/object_template_builder.h"
#include "net/ssl/ssl_cert_request_info.h"
#include "ui/base/l10n/l10n_util.h"
#include "ui/gfx/image/image.h"
#if defined(OS_WIN)
#include "base/strings/utf_string_conversions.h"
#endif
using atom::Browser;
namespace mate {
#if defined(OS_WIN)
template<>
struct Converter<Browser::UserTask> {
  static bool FromV8(v8::Isolate* isolate, v8::Local<v8::Value> val,