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 16caa4ca98f3028a54bacb4fe0613bd60f29ae59..6604bf0c00e91a3ea5cf73303dc81a40ce7799ab 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 SetStandardCursor(Id window_id, mus::mojom::Cursor cursor_id);
   void SetVisible(Id window_id, bool visible);
   void SetProperty(Window* window,
                    const std::string& name,
@@ -174,6 +175,7 @@ class WindowTreeClientImpl : public WindowTreeConnection,
                           Id window_id,
                           mojom::EventPtr event) override;
   void OnWindowFocused(Id focused_window_id) override;
+  void OnWindowCursorChanged(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,