Support paths which are encoded with base64 in http put devfs server code

runtime/bin/vmservice/server.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of vmservice_io;
 
 class WebSocketClient extends Client {
   static const int PARSE_ERROR_CODE = 4000;
   static const int BINARY_MESSAGE_ERROR_CODE = 4001;
   static const int NOT_MAP_ERROR_CODE = 4002;
@@ skipping 172 matching lines @@
     if (!_originCheck(request)) {
       // This is a cross origin attempt to connect
       request.response.close();
       return;
     }
     if (request.method == 'PUT') {
       // PUT requests are forwarded to DevFS for processing.
 
       List fsNameList;
       List fsPathList;
+      List fsPathBase64List;
       Object fsName;
       Object fsPath;
 
       try {
         // Extract the fs name and fs path from the request headers.
         fsNameList = request.headers['dev_fs_name'];
+        fsName = fsNameList[0];
+
         fsPathList = request.headers['dev_fs_path'];
-        fsName = fsNameList[0];
-        fsPath = fsPathList[0];
+        fsPathBase64List = request.headers['dev_fs_path_b64'];
+        // If the 'dev_fs_path_b64' header field was sent, use that instead.
+        if ((fsPathBase64List != null) && (fsPathBase64List.length > 0)) {
+          fsPath = UTF8.decode(BASE64.decode(fsPathBase64List[0]));
+        } else {
+          fsPath = fsPathList[0];
+        }
       } catch (e) { /* ignore */ }
 
       String result;
       try {
         result = await _service.devfs.handlePutStream(
             fsName,
             fsPath,
             request.transform(GZIP.decoder));
       } catch (e) { /* ignore */ }
 
@@ skipping 104 matching lines @@
       _notifyServerState("", 0);
       onServerAddressChange(null);
       return this;
     });
   }
 
 }
 
 void _notifyServerState(String ip, int port)
     native "VMServiceIO_NotifyServerState";