Remove need to instantiate Platform and make methods static.

tests/standalone/src/io/FileErrorTest.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.
 //
 // Dart test program for testing error handling in file I/O.
 
 #import("dart:io");
 #import("dart:isolate");
 
 Directory tempDir() {
   var d = new Directory('');
   d.createTempSync();
   return d;
 }
 
 
 bool checkNonExistentFileException(e, str) {
   Expect.isTrue(e is FileIOException);
   Expect.isTrue(e.osError != null);
   Expect.isTrue(e.toString().indexOf(str) != -1);
-  Platform platform = new Platform();
-  if (platform.operatingSystem() == "linux") {
+  if (Platform.operatingSystem() == "linux") {
     Expect.isTrue(e.toString().indexOf("No such file or directory") != -1);
-  } else if (platform.operatingSystem() == "macos") {
+  } else if (Platform.operatingSystem() == "macos") {
     Expect.isTrue(e.toString().indexOf("No such file or directory") != -1);
-  } else if (platform.operatingSystem() == "windows") {
+  } else if (Platform.operatingSystem() == "windows") {
     Expect.isTrue(
         e.toString().indexOf(
             "The system cannot find the file specified") != -1);
   }
   // File not not found has error code 2 on all supported platforms.
   Expect.equals(2, e.osError.errorCode);
 
   return true;
 }
 
@@ skipping 73 matching lines @@
     checkLengthNonExistentFileException(e);
     p.toSendPort().send(null);
   };
 }
 
 
 bool checkCreateInNonExistentDirectoryException(e) {
   Expect.isTrue(e is FileIOException);
   Expect.isTrue(e.osError != null);
   Expect.isTrue(e.toString().indexOf("Cannot create file") != -1);
-  Platform platform = new Platform();
-  if (platform.operatingSystem() == "linux") {
+  if (Platform.operatingSystem() == "linux") {
     Expect.isTrue(e.toString().indexOf("No such file or directory") != -1);
     Expect.equals(2, e.osError.errorCode);
-  } else if (platform.operatingSystem() == "macos") {
+  } else if (Platform.operatingSystem() == "macos") {
     Expect.isTrue(e.toString().indexOf("No such file or directory") != -1);
     Expect.equals(2, e.osError.errorCode);
-  } else if (platform.operatingSystem() == "windows") {
+  } else if (Platform.operatingSystem() == "windows") {
     Expect.isTrue(
         e.toString().indexOf(
             "The system cannot find the path specified") != -1);
     Expect.equals(3, e.osError.errorCode);
   }
 
   return true;
 }
 
 void testCreateInNonExistentDirectory() {
@@ skipping 13 matching lines @@
   file.onError = (e) {
     checkCreateInNonExistentDirectoryException(e);
     p.toSendPort().send(null);
   };
 }
 
 bool checkFullPathOnNonExistentDirectoryException(e) {
   Expect.isTrue(e is FileIOException);
   Expect.isTrue(e.osError != null);
   Expect.isTrue(e.toString().indexOf("Cannot retrieve full path") != -1);
-  Platform platform = new Platform();
-  if (platform.operatingSystem() == "linux") {
+  if (Platform.operatingSystem() == "linux") {
     Expect.isTrue(e.toString().indexOf("No such file or directory") != -1);
-  } else if (platform.operatingSystem() == "macos") {
+  } else if (Platform.operatingSystem() == "macos") {
     Expect.isTrue(e.toString().indexOf("No such file or directory") != -1);
-  } else if (platform.operatingSystem() == "windows") {
+  } else if (Platform.operatingSystem() == "windows") {
     Expect.isTrue(
         e.toString().indexOf(
             "The system cannot find the file specified") != -1);
   }
   // File not not found has error code 2 on all supported platforms.
   Expect.equals(2, e.osError.errorCode);
 
   return true;
 }
 
@@ skipping 15 matching lines @@
     checkFullPathOnNonExistentDirectoryException(e);
     p.toSendPort().send(null);
   };
 }
 
 bool checkDirectoryInNonExistentDirectoryException(e) {
   Expect.isTrue(e is FileIOException);
   Expect.isTrue(e.osError != null);
   Expect.isTrue(
       e.toString().indexOf("Cannot retrieve directory for file") != -1);
-  Platform platform = new Platform();
-  if (platform.operatingSystem() == "linux") {
+  if (Platform.operatingSystem() == "linux") {
     Expect.isTrue(e.toString().indexOf("No such file or directory") != -1);
-  } else if (platform.operatingSystem() == "macos") {
+  } else if (Platform.operatingSystem() == "macos") {
     Expect.isTrue(e.toString().indexOf("No such file or directory") != -1);
-  } else if (platform.operatingSystem() == "windows") {
+  } else if (Platform.operatingSystem() == "windows") {
     Expect.isTrue(
         e.toString().indexOf(
             "The system cannot find the file specified") != -1);
   }
   // File not not found has error code 2 on all supported platforms.
   Expect.equals(2, e.osError.errorCode);
 
   return true;
 }
 
@@ skipping 242 matching lines @@
   testDirectoryInNonExistentDirectory();
   testReadAsBytesNonExistent();
   testReadAsTextNonExistent();
   testReadAsLinesNonExistent();
   testWriteByteToReadOnlyFile();
   testWriteListToReadOnlyFile();
   testTruncateReadOnlyFile();
   testOperateOnClosedFile();
   testRepeatedlyCloseFile();
 }