Centralize legacy preference storage

src/legacy_canvas_view_services.cpp

@@ -3,9 +3,8 @@
 #include "legacy_canvas_view_services.h"
 
 #include "app.h"
+#include "legacy_preference_storage.h"
 #include "node_canvas.h"
-#include "serializer.h"
-#include "settings.h"
 
 namespace pp::panopainter {
 namespace {
@@ -47,8 +46,7 @@ public:
         }
 
         app_.canvas->set_density(plan.density);
-        Settings::set("vp-scale", Serializer::Float(plan.density));
-        Settings::save();
+        save_legacy_float_preference("vp-scale", plan.density);
     }
 
     void set_cursor_mode(const pp::app::CanvasViewCursorModePlan& plan) override
@@ -59,8 +57,8 @@ public:
 
         const auto mode = static_cast<int>(plan.mode);
         app_.canvas->set_cursor_visibility(static_cast<NodeCanvas::kCursorVisibility>(mode));
-        Settings::set("show-cursor", Serializer::Integer(mode));
-        Settings::save();
+        set_legacy_integer_preference("show-cursor", mode);
+        save_legacy_preferences();
     }
 
 private: