Add getter for lineMode and echoMode for Stdin.

sdk/lib/_internal/lib/io_patch.dart

Index: sdk/lib/_internal/lib/io_patch.dart
diff --git a/sdk/lib/_internal/lib/io_patch.dart b/sdk/lib/_internal/lib/io_patch.dart
index 426992b6805494905a3d21dd172ac7768c674e53..2f3db18fd1214d8b258f6bd19697cd54997a0cd4 100644
--- a/sdk/lib/_internal/lib/io_patch.dart
+++ b/sdk/lib/_internal/lib/io_patch.dart
@@ -343,9 +343,15 @@ patch class Stdin {
   patch int readByteSync() {
     throw new UnsupportedError("Stdin.readByteSync");
   }
+  patch bool get echoMode {
+    throw new UnsupportedError("Stdin.echoMode");
+  }
   patch void set echoMode(bool enabled) {
     throw new UnsupportedError("Stdin.echoMode");
   }
+  patch bool get lineMode {
+    throw new UnsupportedError("Stdin.lineMode");
+  }
   patch void set lineMode(bool enabled) {
     throw new UnsupportedError("Stdin.lineMode");
   }