rename no-package-libraries to dart-internal-objects (flutter#4954)

Author: polina-c

packages/devtools_app/lib/src/screens/memory/panes/diff/widgets/class_filter_dialog.dart

@@ -135,5 +135,5 @@ const _helpText = 'Choose and customize the filter.\n'
     '  MyClass\n'
     '  package:myPackage/src/\n\n'
     'Specify:\n'
-    '  - ${ClassFilter.noPackageLibrariesAlias} for classes without package prefix\n'
+    '  - ${ClassFilter.dartInternalAlias} for dart internal objects, not assigned to any package\n'
     '  - ${ClassFilter.dartAndFlutterLibrariesAlias} for most "dart:" and "package:" libraries published by Dart and Flutter orgs.';

packages/devtools_app/lib/src/screens/memory/shared/heap/class_filter.dart

@@ -36,15 +36,15 @@ class ClassFilter {
   ClassFilter.empty()
       : this(
           filterType: ClassFilterType.showAll,
-          except: '$noPackageLibrariesAlias\n$dartAndFlutterLibrariesAlias',
+          except: '$dartInternalAlias\n$dartAndFlutterLibrariesAlias',
           only: null,
         );
 
   static String _trimByLine(String value) =>
       value.split('\n').map((e) => e.trim()).join('\n');
 
   static const String dartAndFlutterLibrariesAlias = '\$dart-flutter-libraries';
-  static const String noPackageLibrariesAlias = '\$no-package-libraries';
+  static const String dartInternalAlias = '\$dart-internal-objects';
 
   final ClassFilterType filterType;
   final String except;
@@ -140,8 +140,7 @@ class ClassFilter {
     if (className.fullName.contains(filter)) return true;
     if (filter == dartAndFlutterLibrariesAlias && className.isDartOrFlutter)
       return true;
-    if (filter == noPackageLibrariesAlias && className.isPackageless)
-      return true;
+    if (filter == dartInternalAlias && className.isPackageless) return true;
     return false;
   }
 }