Allow weird characters (like ?) to appear in devfs filenames.

sdk/lib/vmservice/devfs.dart

Index: sdk/lib/vmservice/devfs.dart
diff --git a/sdk/lib/vmservice/devfs.dart b/sdk/lib/vmservice/devfs.dart
index 35af74822d7b27accf8b66c60175c7cdcab29576..47355127ed5367aca4da4bc1d5a47103e7c28543 100644
--- a/sdk/lib/vmservice/devfs.dart
+++ b/sdk/lib/vmservice/devfs.dart
@@ -37,10 +37,18 @@ class _FileSystem {
     }
     Uri pathUri;
     try {
-      pathUri = Uri.parse(path);
+      pathUri = new Uri.file(path);
     } on FormatException catch(e) {
       return null;
     }
+
+    try {
+      // Make sure that this pathUri can be converted to a file path.
+      pathUri.toFilePath();
+    } on UnsupportedError catch (e) {
+      return null;
+    }
+
     Uri resolvedUri = uri.resolveUri(pathUri);
     if (!resolvedUri.toString().startsWith(uri.toString())) {
       // Resolved uri must be within the filesystem's base uri.
@@ -313,6 +321,10 @@ class DevFS {
       return _encodeFileSystemDoesNotExistError(message, fsName);
     }
     var fileList = await listFiles(fs.uri);
+    // Remove any url-encoding in the filenames.
+    for (int i = 0; i < fileList.length; i++) {
+      fileList[i]['name'] = Uri.decodeFull(fileList[i]['name']);
+    }
     var result = { 'type': 'FSFileList', 'files': fileList };
     return encodeResult(message, result);
   }