text input focus: Supports Window::GetFocusedTextInputClient.

ash/display/cursor_window_controller.cc

Index: ash/display/cursor_window_controller.cc
diff --git a/ash/display/cursor_window_controller.cc b/ash/display/cursor_window_controller.cc
index 3300d32ef230e15754c297e5b1420c9ef39560c4..a59a5d83ad9e1ca97e3dc32fba61c5489d6e1324 100644
--- a/ash/display/cursor_window_controller.cc
+++ b/ash/display/cursor_window_controller.cc
@@ -33,6 +33,7 @@ class CursorWindowDelegate : public aura::WindowDelegate {
   gfx::Size GetMaximumSize() const override { return size_; }
   void OnBoundsChanged(const gfx::Rect& old_bounds,
                        const gfx::Rect& new_bounds) override {}
+  ui::TextInputClient* GetFocusedTextInputClient() override { return nullptr; }
   gfx::NativeCursor GetCursor(const gfx::Point& point) override {
     return gfx::kNullCursor;
   }