IDEA-154631 wrong directory's icon

caused by: IDEA-149590 Open File dialog should display icons for registered directory types (e.g. bundles on OS X)
we now only show directory icons for specific file types (namely DirectoryFileTypes)

platform/core-api/src/com/intellij/ide/presentation/VirtualFilePresentation.java

@@ -16,8 +16,8 @@
 package com.intellij.ide.presentation;
 
 import com.intellij.ide.TypePresentationService;
+import com.intellij.openapi.fileTypes.DirectoryFileType;
 import com.intellij.openapi.fileTypes.FileType;
-import com.intellij.openapi.fileTypes.UnknownFileType;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.util.IconUtil;
 import com.intellij.util.PlatformIcons;
@@ -40,7 +40,7 @@ public class VirtualFilePresentation {
       return icon;
     }
     FileType fileType = vFile.getFileType();
-    if (fileType == UnknownFileType.INSTANCE && vFile.isDirectory() && vFile.isInLocalFileSystem()) {
+    if (vFile.isDirectory() && vFile.isInLocalFileSystem() && !(fileType instanceof DirectoryFileType)) {
       return PlatformIcons.FOLDER_ICON;
     }
     return fileType.getIcon();

platform/core-api/src/com/intellij/openapi/fileTypes/DirectoryFileType.java

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2000-2016 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.intellij.openapi.fileTypes;
+
+/**
+ * Use this marker interface to indicate that the file type signifies a directory (not a file)
+ */
+public interface DirectoryFileType extends FileType {
+}