Error checking for Stdio calls

runtime/bin/stdio_fuchsia.cc

 // Copyright (c) 2016, 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.
 
 #if !defined(DART_IO_DISABLED)
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_FUCHSIA)
 
 #include "bin/stdio.h"
 
 namespace dart {
 namespace bin {
 
-int Stdin::ReadByte() {
-  UNIMPLEMENTED();
-  return -1;
-}
-
-
-bool Stdin::GetEchoMode() {
+bool Stdin::ReadByte(int* byte) {
   UNIMPLEMENTED();
   return false;
 }
 
 
-void Stdin::SetEchoMode(bool enabled) {
-  UNIMPLEMENTED();
-}
-
-
-bool Stdin::GetLineMode() {
+bool Stdin::GetEchoMode(bool* enabled) {
   UNIMPLEMENTED();
   return false;
 }
 
 
-void Stdin::SetLineMode(bool enabled) {
+bool Stdin::SetEchoMode(bool enabled) {
   UNIMPLEMENTED();
+  return false;
 }
 
 
+bool Stdin::GetLineMode(bool* enabled) {
+  UNIMPLEMENTED();
+  return false;
+}
+
+
+bool Stdin::SetLineMode(bool enabled) {
+  UNIMPLEMENTED();
+  return false;
+}
+
+
 bool Stdout::GetTerminalSize(intptr_t fd, int size[2]) {
   UNIMPLEMENTED();
   return false;
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_FUCHSIA)
 
 #endif  // !defined(DART_IO_DISABLED)