Support for excluded files/folders.

pkg/analyzer/lib/file_system/physical_file_system.dart

Index: pkg/analyzer/lib/file_system/physical_file_system.dart
diff --git a/pkg/analyzer/lib/file_system/physical_file_system.dart b/pkg/analyzer/lib/file_system/physical_file_system.dart
index 4a4298d30377c32e86bcb98c51191e3de8c46a13..55c778e76dc8f056a8e58f05de0ec9ce792d92ee 100644
--- a/pkg/analyzer/lib/file_system/physical_file_system.dart
+++ b/pkg/analyzer/lib/file_system/physical_file_system.dart
@@ -55,6 +55,11 @@ class _PhysicalFile extends _PhysicalResource implements File {
     }
     return new FileBasedSource.con2(uri, javaFile);
   }
+
+  @override
+  bool isOrContains(String path) {
+    return path == this.path;
+  }
 }
 
 
@@ -99,6 +104,14 @@ class _PhysicalFolder extends _PhysicalResource implements Folder {
     }
     return children;
   }
+
+  @override
+  bool isOrContains(String path) {
+    if (path == this.path) {
+      return true;
+    }
+    return contains(path);
+  }
 }