Add RandomAccessFile.read method and use it for file input stream.

runtime/bin/file_patch.dart

Index: runtime/bin/file_patch.dart
diff --git a/runtime/bin/file_patch.dart b/runtime/bin/file_patch.dart
index 4ca5733e69d797b32d916df344bf1d6addeb7864..eb55dae6abff5553267bfadbb1f0f17f5442619f 100644
--- a/runtime/bin/file_patch.dart
+++ b/runtime/bin/file_patch.dart
@@ -21,6 +21,7 @@ patch class _File {
 patch class _RandomAccessFile {
   /* patch */ static int _close(int id) native "File_Close";
   /* patch */ static _readByte(int id) native "File_ReadByte";
+  /* patch */ static _read(int id, int bytes) native "File_Read";
   /* patch */ static _readList(int id, List<int> buffer, int offset, int bytes)
       native "File_ReadList";
   /* patch */ static _writeByte(int id, int value) native "File_WriteByte";