Remove need to instantiate Platform and make methods static.

tests/standalone/src/io/FileErrorTest.dart

Index: tests/standalone/src/io/FileErrorTest.dart
diff --git a/tests/standalone/src/io/FileErrorTest.dart b/tests/standalone/src/io/FileErrorTest.dart
index 295dfbc7d544efe86f89c093854cd000df572f00..40f2b62c9b3b2cfb7c4a05c7efecd16e7b0683f7 100644
--- a/tests/standalone/src/io/FileErrorTest.dart
+++ b/tests/standalone/src/io/FileErrorTest.dart
@@ -18,12 +18,11 @@ 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);
@@ -117,14 +116,13 @@ 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);
@@ -158,12 +156,11 @@ 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);
@@ -199,12 +196,11 @@ bool checkDirectoryInNonExistentDirectoryException(e) {
   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);