Remove uses of Path class from tests/standalone.

tests/standalone/coverage_test.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.
 
 // This test forks a second vm process that runs the script tools/coverage.dart
 // and verifies that the coverage tool produces its expected output.
 // This test is mainly here to ensure that the coverage tool compiles and
 // runs.
 
 import "dart:io";
 import "dart:async";
+import "package:path/path.dart";
 
 // Coverage tool script relative to the path of this test.
 var coverageToolScript = "../../tools/coverage.dart";
 
 // Coverage target script relative to this test.
 var coverageTargetScript = "../language/hello_dart_test.dart";
 var targPath;
 
 Process coverageToolProcess;
 List sourceLines;
@@ skipping 20 matching lines @@
     print("Successfully matched all lines of '$targPath'");
   } else {
     print("Error: could not match all source code lines of '$targPath'");
     exit(-1);
   }
 }
 
 void main() {
   // Compute paths for coverage tool and coverage target relative
   // the the path of this script.
-  var scriptPath = new Path(Platform.script).directoryPath;
-  var toolPath = scriptPath.join(new Path(coverageToolScript)).canonicalize();
-  targPath = scriptPath.join(new Path(coverageTargetScript)).canonicalize();
+  var scriptPath = dirname(Platform.script);
+  var toolPath = normalize(join(scriptPath, coverageToolScript));
+  targPath = normalize(join(scriptPath, coverageTargetScript));
 
-  sourceLines = new File(targPath.toNativePath()).readAsLinesSync();
+  sourceLines = new File(targPath).readAsLinesSync();
   assert(sourceLines != null);
 
-  var processOpts = [ "--compile_all",
-                      toolPath.toNativePath(),
-                      targPath.toNativePath() ];
+  var processOpts = [ "--compile_all", toolPath, targPath ];
 
   Process.start(Platform.executable, processOpts).then((Process process) {
     coverageToolProcess = process;
     coverageToolProcess.stdin.close();
     var stdoutStringStream = coverageToolProcess.stdout
         .transform(new StringDecoder())
         .transform(new LineTransformer());
 
     var stderrStringStream = coverageToolProcess.stderr
         .transform(new StringDecoder())
         .transform(new LineTransformer());
 
     // Wait for 3 future events: stdout and stderr streams of the coverage
     // tool process closed, and coverage tool process terminated.
     var futures = [];
     var subscription = stdoutStringStream.listen(onCoverageOutput);
     futures.add(subscription.asFuture(true));
     subscription = stderrStringStream.listen(onCoverageOutput);
     futures.add(subscription.asFuture(true));
     futures.add(coverageToolProcess.exitCode.then(checkExitCode));
     Future.wait(futures).then((results) {
       checkSuccess();
       if (results.contains(false)) exit(-1);
     });
   });
 }