Remove dart:platform library.

sdk/lib/io/platform.dart

Index: sdk/lib/io/platform.dart
diff --git a/sdk/lib/io/platform.dart b/sdk/lib/io/platform.dart
index 1053d375205156a07cbfacf7d7ae2c3398dab836..11dee794cbd5af3b225617463db80e34049f231c 100644
--- a/sdk/lib/io/platform.dart
+++ b/sdk/lib/io/platform.dart
@@ -5,19 +5,8 @@
 part of dart.io;
 
 /**
- * Deprecated: the [Platform] class exposes details of the machine and operating
+ * The [Platform] class exposes details of the machine and operating
  * system.
- *
- * This class has been replaced by adding the dart:platform library to Dart.
- * dart:platform is available on all browser and standalone platforms,
- * including Dart code that has been compiled to javascript.
- *
- * The dart:platform class has
- * the same top-level getters as the members of [Platform], except that the
- * [isWindows], [isLinux], [isAndroid], and [isMacOS] getters
- * have been removed. On platforms supporting dart:io, the getters of
- * dart:platform have the same values as the Platform class members, except
- * that [script] has been changed from a [String] to a file [Uri].
  */
 @deprecated
 class Platform {