Ability to import .escn files, which is just a .tscn but with forced import.

This works together with the new Blender to Godot exporter.

(cherry picked from commit 1322ca6fb2)

editor/editor_node.cpp

@@ -4815,6 +4815,10 @@ EditorNode::EditorNode() {
 			Ref<EditorSceneImporterGLTF> import_gltf;
 			import_gltf.instance();
 			import_scene->add_importer(import_gltf);
+
+			Ref<EditorSceneImporterESCN> import_escn;
+			import_escn.instance();
+			import_scene->add_importer(import_escn);
 		}
 
 		Ref<ResourceImporterBitMap> import_bitmap;

editor/import/resource_importer_scene.cpp

@@ -46,6 +46,7 @@
 #include "scene/resources/box_shape.h"
 #include "scene/resources/plane_shape.h"
 #include "scene/resources/ray_shape.h"
+#include "scene/resources/scene_format_text.h"
 #include "scene/resources/sphere_shape.h"
 
 uint32_t EditorSceneImporter::get_import_flags() const {
@@ -1395,3 +1396,25 @@ ResourceImporterScene *ResourceImporterScene::singleton = NULL;
 ResourceImporterScene::ResourceImporterScene() {
 	singleton = this;
 }
+///////////////////////////////////////
+
+uint32_t EditorSceneImporterESCN::get_import_flags() const {
+	return IMPORT_SCENE;
+}
+void EditorSceneImporterESCN::get_extensions(List<String> *r_extensions) const {
+	r_extensions->push_back("escn");
+}
+Node *EditorSceneImporterESCN::import_scene(const String &p_path, uint32_t p_flags, int p_bake_fps, List<String> *r_missing_deps, Error *r_err) {
+
+	Error error;
+	Ref<PackedScene> ps = ResourceFormatLoaderText::singleton->load(p_path, p_path, &error);
+	ERR_FAIL_COND_V(!ps.is_valid(), NULL);
+
+	Node *scene = ps->instance();
+	ERR_FAIL_COND_V(!scene, NULL);
+
+	return scene;
+}
+Ref<Animation> EditorSceneImporterESCN::import_animation(const String &p_path, uint32_t p_flags, int p_bake_fps) {
+	ERR_FAIL_V(Ref<Animation>());
+}

editor/import/resource_importer_scene.h

@@ -155,4 +155,14 @@ public:
 	ResourceImporterScene();
 };
 
+class EditorSceneImporterESCN : public EditorSceneImporter {
+	GDCLASS(EditorSceneImporterESCN, EditorSceneImporter);
+
+public:
+	virtual uint32_t get_import_flags() const;
+	virtual void get_extensions(List<String> *r_extensions) const;
+	virtual Node *import_scene(const String &p_path, uint32_t p_flags, int p_bake_fps, List<String> *r_missing_deps, Error *r_err = NULL);
+	virtual Ref<Animation> import_animation(const String &p_path, uint32_t p_flags, int p_bake_fps);
+};
+
 #endif // RESOURCEIMPORTERSCENE_H

scene/resources/scene_format_text.cpp

@@ -1312,6 +1312,8 @@ Error ResourceFormatLoaderText::rename_dependencies(const String &p_path, const
 	return ria->rename_dependencies(f, p_path, p_map);
 }
 
+ResourceFormatLoaderText *ResourceFormatLoaderText::singleton = NULL;
+
 Error ResourceFormatLoaderText::convert_file_to_binary(const String &p_src_path, const String &p_dst_path) {
 
 	Error err;

scene/resources/scene_format_text.h

@@ -128,7 +128,9 @@ public:
 };
 
 class ResourceFormatLoaderText : public ResourceFormatLoader {
+
 public:
+	static ResourceFormatLoaderText *singleton;
 	virtual Ref<ResourceInteractiveLoader> load_interactive(const String &p_path, const String &p_original_path = "", Error *r_error = NULL);
 	virtual void get_recognized_extensions_for_type(const String &p_type, List<String> *p_extensions) const;
 	virtual void get_recognized_extensions(List<String> *p_extensions) const;
@@ -138,6 +140,8 @@ public:
 	virtual Error rename_dependencies(const String &p_path, const Map<String, String> &p_map);
 
 	static Error convert_file_to_binary(const String &p_src_path, const String &p_dst_path);
+
+	ResourceFormatLoaderText() { singleton = this; }
 };
 
 class ResourceFormatSaverTextInstance {