- 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
auto browser = base::Unretained(Browser::Get());
  mate::ObjectTemplateBuilder(isolate, prototype)
      .SetMethod("quit", base::Bind(&Browser::Quit, browser))
      .SetMethod("exit", base::Bind(&Browser::Exit, browser))
      .SetMethod("focus", base::Bind(&Browser::Focus, browser))
      .SetMethod("getVersion", base::Bind(&Browser::GetVersion, browser))
      .SetMethod("setVersion", base::Bind(&Browser::SetVersion, browser))
      .SetMethod("getName", base::Bind(&Browser::GetName, browser))
      .SetMethod("setName", base::Bind(&Browser::SetName, browser))
      .SetMethod("isReady", base::Bind(&Browser::is_ready, browser))
      .SetMethod("addRecentDocument",
                 base::Bind(&Browser::AddRecentDocument, browser))
      .SetMethod("clearRecentDocuments",
                 base::Bind(&Browser::ClearRecentDocuments, browser))
      .SetMethod("setAppUserModelId",
                 base::Bind(&Browser::SetAppUserModelID, browser))
      .SetMethod("isDefaultProtocolClient",
                 base::Bind(&Browser::IsDefaultProtocolClient, browser))
      .SetMethod("setAsDefaultProtocolClient",
                 base::Bind(&Browser::SetAsDefaultProtocolClient, browser))
      .SetMethod("removeAsDefaultProtocolClient",
                 base::Bind(&Browser::RemoveAsDefaultProtocolClient, browser))
      .SetMethod("setBadgeCount", base::Bind(&Browser::SetBadgeCount, browser))
      .SetMethod("getBadgeCount", base::Bind(&Browser::GetBadgeCount, browser))
#if defined(OS_MACOSX)
      .SetMethod("hide", base::Bind(&Browser::Hide, browser))
      .SetMethod("show", base::Bind(&Browser::Show, browser))
      .SetMethod("setUserActivity",
                 base::Bind(&Browser::SetUserActivity, browser))
      .SetMethod("getCurrentActivityType",