Do some housekeeping in tools/testing/dart

tools/testing/dart/test_suite.dart

 // Copyright (c) 2012, 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.
 
 /**
  * Classes and methods for enumerating and preparing tests.
  *
  * This library includes:
  *
  * - Creating tests by listing all the Dart files in certain directories,
@@ skipping 1061 matching lines @@
       var path = info.filePath;
       if (vmOptionsVarient != 0) {
         // Ensure a unique directory for each test case.
         path = path.join(new Path(vmOptionsVarient.toString()));
       }
       tempDir = createCompilationOutputDirectory(path);
 
       List<String> otherResources = info.optionsFromFile['otherResources'];
       for (String name in otherResources) {
         Path namePath = new Path(name);
-        String fileName = namePath.filename;
         Path fromPath = info.filePath.directoryPath.join(namePath);
         new File('$tempDir/$name').parent.createSync(recursive: true);
         new File(fromPath.toNativePath()).copySync('$tempDir/$name');
       }
     }
 
     CommandArtifact compilationArtifact =
         compilerConfiguration.computeCompilationArtifact(
             buildDir,
             tempDir,
@@ skipping 71 matching lines @@
     if (fileString.startsWith(buildDir.toString())) {
       var fileRelativeToBuildDir = file.relativeTo(buildDir);
       return "/$PREFIX_BUILDDIR/$fileRelativeToBuildDir";
     } else if (fileString.startsWith(dartDir.toString())) {
       var fileRelativeToDartDir = file.relativeTo(dartDir);
       return "/$PREFIX_DARTDIR/$fileRelativeToDartDir";
     }
     // Unreachable
     print("Cannot create URL for path $file. Not in build or dart directory.");
     exit(1);
+    return null;
   }
 
   Uri _getUriForBrowserTest(String pathComponent, String subtestName) {
     // Note: If we run test.py with the "--list" option, no http servers
     // will be started. So we return a dummy url instead.
     if (configuration['list']) {
       return Uri.parse('http://listing_the_tests_only');
     }
     assert(configuration.containsKey('_servers_'));
     int serverPort = configuration['_servers_'].port;
@@ skipping 1346 matching lines @@
       }
       if (path.length > WINDOWS_SHORTEN_PATH_LIMIT) {
         ++shortNameCounter;
         var pathEnd = path.substring(path.length - WINDOWS_PATH_END_LENGTH);
         path = "short${shortNameCounter}_$pathEnd";
       }
     }
     return path;
   }
 }