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

runtime/observatory/tests/service/dev_fs_test.dart

Index: runtime/observatory/tests/service/dev_fs_test.dart
diff --git a/runtime/observatory/tests/service/dev_fs_test.dart b/runtime/observatory/tests/service/dev_fs_test.dart
index 5b2930d775ac521d4bdc8065efe3fe0ad77fca90..df99ef6aadc335e01a9bdbd929ce12282d073b14 100644
--- a/runtime/observatory/tests/service/dev_fs_test.dart
+++ b/runtime/observatory/tests/service/dev_fs_test.dart
@@ -153,6 +153,50 @@ var tests = [
     });
     expect(result['type'], equals('Success'));
   },
+
+  // Write a file with the ? character in the filename.
+  (VM vm) async {
+    var fsId = 'test';
+    var filePath = '/foo/bar?dat';
+    var fileContents = BASE64.encode(UTF8.encode('fileContents'));
+
+    var result;
+    // Create DevFS.
+    result = await vm.invokeRpcNoUpgrade('_createDevFS', { 'fsName': fsId });
+    expect(result['type'], equals('FileSystem'));
+    expect(result['name'], equals(fsId));
+    expect(result['uri'], new isInstanceOf<String>());
+
+    // Write the file.
+    result = await vm.invokeRpcNoUpgrade('_writeDevFSFile', {
+        'fsName': fsId,
+        'path': filePath,
+        'fileContents': fileContents
+    });
+    expect(result['type'], equals('Success'));
+
+    // Read the file back.
+    result = await vm.invokeRpcNoUpgrade('_readDevFSFile', {
+        'fsName': fsId,
+        'path': filePath,
+    });
+    expect(result['type'], equals('FSFile'));
+    expect(result['fileContents'], equals(fileContents));
+
+    // List all the files in the file system.
+    result = await vm.invokeRpcNoUpgrade('_listDevFSFiles', {
+        'fsName': fsId,
+    });
+    expect(result['type'], equals('FSFileList'));
+    expect(result['files'].length, equals(1));
+    expect(result['files'][0]['name'], equals('/foo/bar?dat'));
+
+    // Delete DevFS.
+    result = await vm.invokeRpcNoUpgrade('_deleteDevFS', {
+        'fsName': fsId,
+    });
+    expect(result['type'], equals('Success'));
+  },
 ];
 
 main(args) async => runVMTests(args, tests);