mus: Let clients set the cursor of their window.

components/mus/public/cpp/lib/window_tree_client_impl.h

Index: components/mus/public/cpp/lib/window_tree_client_impl.h
diff --git a/components/mus/public/cpp/lib/window_tree_client_impl.h b/components/mus/public/cpp/lib/window_tree_client_impl.h
index c6c4ecd74001c7b37f14f4a341047f0a7c99b42e..8a0b9b9988c06412ee3feea15136a45fc6390a14 100644
--- a/components/mus/public/cpp/lib/window_tree_client_impl.h
+++ b/components/mus/public/cpp/lib/window_tree_client_impl.h
@@ -67,6 +67,7 @@ class WindowTreeClientImpl : public WindowTreeConnection,
   void SetClientArea(Id window_id, const gfx::Insets& client_area);
   void SetFocus(Id window_id);
   void SetCanFocus(Id window_id, bool can_focus);
+  void SetPredefinedCursor(Id window_id, mus::mojom::Cursor cursor_id);
   void SetVisible(Window* window, bool visible);
   void SetProperty(Window* window,
                    const std::string& name,
@@ -174,6 +175,8 @@ class WindowTreeClientImpl : public WindowTreeConnection,
                           Id window_id,
                           mojom::EventPtr event) override;
   void OnWindowFocused(Id focused_window_id) override;
+  void OnWindowPredefinedCursorChanged(Id window_id,
+                                       mojom::Cursor cursor) override;
   void OnChangeCompleted(uint32_t change_id, bool success) override;
   void WmSetBounds(uint32_t change_id,
                    Id window_id,