Added a class acting as a fake caret for accessibility.

ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc

Index: ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc
diff --git a/ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc b/ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc
index fd25fc60ae0bd0331902c8d0ece1610699c563d1..993f29c851bbfead2b712d3e942ce24f986d9131 100644
--- a/ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc
+++ b/ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc
@@ -600,6 +600,14 @@ void DesktopWindowTreeHostWin::OnWindowHidingAnimationCompleted() {
 ////////////////////////////////////////////////////////////////////////////////
 // DesktopWindowTreeHostWin, HWNDMessageHandlerDelegate implementation:
 
+void DesktopWindowTreeHostWin::AddInputMethodObserver() const {
+  GetInputMethod()->AddObserver(message_handler_);
+}
+
+void DesktopWindowTreeHostWin::RemoveInputMethodObserver() const {
+  GetInputMethod()->RemoveObserver(message_handler_);
+}
+
 bool DesktopWindowTreeHostWin::HasNonClientView() const {
   return has_non_client_view_;
 }