Thin retained app and render runtime seams

src/legacy_document_image_import_services.cpp

@@ -0,0 +1,57 @@
+#include "pch.h"
+
+#include "legacy_document_image_import_services.h"
+
+#include "canvas.h"
+#include "canvas_modes.h"
+
+#include <utility>
+
+namespace pp::panopainter {
+namespace {
+
+class LegacyDocumentImageImportServices final : public pp::app::DocumentImageImportServices {
+public:
+    LegacyDocumentImageImportServices(Canvas* canvas, CanvasModeTransform* import_mode, Image image) noexcept
+        : canvas_(canvas)
+        , import_mode_(import_mode)
+        , image_(std::move(image))
+    {
+    }
+
+    void import_equirectangular(std::string_view import_path) override
+    {
+        if (canvas_)
+            canvas_->import_equirectangular(std::string(import_path));
+    }
+
+    void enter_transform_import(std::string_view) override
+    {
+        if (!canvas_ || !import_mode_)
+            return;
+
+        import_mode_->m_action = CanvasModeTransform::ActionType::Import;
+        import_mode_->m_source_image = std::move(image_);
+        Canvas::set_mode(kCanvasMode::Import);
+    }
+
+private:
+    Canvas* canvas_ = nullptr;
+    CanvasModeTransform* import_mode_ = nullptr;
+    Image image_;
+};
+
+} // namespace
+
+pp::foundation::Status execute_legacy_document_image_import_plan(
+    const pp::app::DocumentImageImportPlan& plan,
+    std::string_view path,
+    Canvas* canvas,
+    CanvasModeTransform* import_mode,
+    Image image)
+{
+    LegacyDocumentImageImportServices services(canvas, import_mode, std::move(image));
+    return pp::app::execute_document_image_import_plan(plan, path, services);
+}
+
+} // namespace pp::panopainter