Revert "Change dart:io Platform.script to return a Uri."

pkg/analyzer/lib/src/services/runtime/coverage/coverage_impl.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.
 
 /// A library for code coverage support for Dart.
 library runtime.coverage.impl;
 
 import 'dart:async';
 import 'dart:collection' show SplayTreeMap;
 import 'dart:io';
@@ skipping 172 matching lines @@
       }).catchError((e) {
         log.severe('Error in receiving statistics $e.');
         return request.response.close();
       });
     });
   }
 
   String rewritePathContent(String path) {
     if (path.endsWith('__coverage_lib.dart')) {
       String implPath = pathos.joinAll([
-          pathos.dirname(Platform.script.toFilePath()),
+          pathos.dirname(Platform.script),
           '..', 'lib', 'src', 'services', 'runtime', 'coverage',
           'coverage_lib.dart']);
       var content = new File(implPath).readAsStringSync();
       return content.replaceAll('0; // replaced during rewrite', '$port;');
     }
     return null;
   }
 
   bool shouldRewriteFile(String path) {
     if (pathos.extension(path).toLowerCase() != '.dart') return false;
@@ skipping 127 matching lines @@
     var lastOffset = 0;
     offsetFragmentMap.forEach((offset, fragment) {
       sb.write(_code.substring(lastOffset, offset));
       sb.write(fragment);
       lastOffset = offset;
     });
     sb.write(_code.substring(lastOffset, _code.length));
     return sb.toString();
   }
 }