pkg/docgen: moved model classes into minilibs

pkg/docgen/lib/src/models/owned_indexable.dart

+library docgen.models.owned_indexable;
+
+import '../exports/mirrors_util.dart' as dart2js_util;
+import '../exports/source_mirrors.dart';
+
+import '../library_helpers.dart';
+import '../mdn.dart';
+import '../package_helpers.dart';
+
+import 'annotation.dart';
+import 'indexable.dart';
+import 'model_helpers.dart';
+
+abstract class OwnedIndexable<TMirror extends DeclarationMirror>
+    extends Indexable<TMirror> {
+  /// List of the meta annotations on this item.
+  final List<Annotation> annotations;
+
+  /// The object one scope-level above which this item is defined.
+  ///
+  /// Ex: The owner for a top level class, would be its enclosing library.
+  /// The owner of a local variable in a method would be the enclosing method.
+  final Indexable owner;
+
+  /// Returns this object's qualified name, but following the conventions
+  /// we're using in Dartdoc, which is that library names with dots in them
+  /// have them replaced with hyphens.
+  String get docName => owner.docName + '.' + dart2js_util.nameOf(mirror);
+
+  OwnedIndexable(DeclarationMirror mirror, Indexable owner)
+      : annotations = createAnnotations(mirror, owner.owningLibrary),
+        this.owner = owner,
+        super(mirror);
+
+  /// Generates MDN comments from database.json.
+  String getMdnComment() {
+    var domAnnotation = this.annotations.firstWhere(
+        (e) => e.mirror.qualifiedName == #metadata.DomName,
+        orElse: () => null);
+    if (domAnnotation == null) return '';
+    var domName = domAnnotation.parameters.single;
+
+    return mdnComment(rootDirectory, logger, domName);
+  }
+
+  String get packagePrefix => owner.packagePrefix;
+}