Fuchsia: Build standalone VM. Make it run "Hello, World!".

runtime/bin/vmservice_impl.cc

Index: runtime/bin/vmservice_impl.cc
diff --git a/runtime/bin/vmservice_impl.cc b/runtime/bin/vmservice_impl.cc
index cfb05caf00cfcf5534e207ba16e0fa0eddf44584..9a28b20e0939b199280b26fd9750d91c48ea0e80 100644
--- a/runtime/bin/vmservice_impl.cc
+++ b/runtime/bin/vmservice_impl.cc
@@ -246,14 +246,14 @@ bool VmService::Setup(const char* server_ip,
                          DartUtils::NewString("_originCheckDisabled"),
                          Dart_NewBoolean(dev_mode_server));
 
-  // Are we running on Windows?
-#if defined(TARGET_OS_WINDOWS)
-  Dart_Handle is_windows = Dart_True();
+  // Signals not supported on Windows or Fuchsia.
+#if defined(TARGET_OS_WINDOWS) || defined(TARGET_OS_FUCHSIA)
+  Dart_Handle has_signals = Dart_False();
 #else
-  Dart_Handle is_windows = Dart_False();
+  Dart_Handle has_signals = Dart_True();
 #endif
-  result =
-      Dart_SetField(library, DartUtils::NewString("_isWindows"), is_windows);
+  result = Dart_SetField(library,
+      DartUtils::NewString("_hasSignals"), has_signals);
   SHUTDOWN_ON_ERROR(result);
 
   // Get _getWatchSignalInternal from dart:io.