Provide stdout and stderr output in the Observatory debugger.

runtime/vm/dart_api_impl.cc

Index: runtime/vm/dart_api_impl.cc
diff --git a/runtime/vm/dart_api_impl.cc b/runtime/vm/dart_api_impl.cc
index 99e9a559bad7bb12151f6bce0e208c75782ef4da..4cee7e86fe666c40a492fbf8786145044225e996 100644
--- a/runtime/vm/dart_api_impl.cc
+++ b/runtime/vm/dart_api_impl.cc
@@ -5692,6 +5692,67 @@ DART_EXPORT void Dart_RegisterRootServiceRequestCallback(
 }
 
 
+DART_EXPORT Dart_Handle Dart_SetServiceStreamCallbacks(
+    Dart_ServiceStreamListenCallback listen_callback,
+    Dart_ServiceStreamCancelCallback cancel_callback) {
+  if (listen_callback != NULL) {
+    if (Service::stream_listen_callback() != NULL) {
+      return Api::NewError(
+          "%s permits only one listen callback to be registered, please "
+          "remove the existing callback and then add this callback",
+          CURRENT_FUNC);
+    }
+  } else {
+    if (Service::stream_listen_callback() == NULL) {
+      return Api::NewError(
+          "%s expects 'listen_callback' to be present in the callback set.",
+          CURRENT_FUNC);
+    }
+  }
+  if (cancel_callback != NULL) {
+    if (Service::stream_cancel_callback() != NULL) {
+      return Api::NewError(
+          "%s permits only one cancel callback to be registered, please "
+          "remove the existing callback and then add this callback",
+          CURRENT_FUNC);
+    }
+  } else {
+    if (Service::stream_cancel_callback() == NULL) {
+      return Api::NewError(
+          "%s expects 'cancel_callback' to be present in the callback set.",
+          CURRENT_FUNC);
+    }
+  }
+  Service::SetEmbedderStreamCallbacks(listen_callback, cancel_callback);
+  return Api::Success();
+}
+
+
+DART_EXPORT Dart_Handle Dart_ServiceSendDataEvent(const char* stream_id,
+                                                  const char* event_kind,
+                                                  const uint8_t* bytes,
+                                                  intptr_t bytes_length) {
+  Isolate* isolate = Isolate::Current();
+  DARTSCOPE(isolate);
+  if (stream_id == NULL) {
+    RETURN_NULL_ERROR(stream_id);
+  }
+  if (event_kind == NULL) {
+    RETURN_NULL_ERROR(event_kind);
+  }
+  if (bytes == NULL) {
+    RETURN_NULL_ERROR(bytes);
+  }
+  if (bytes_length < 0) {
+    return Api::NewError("%s expects argument 'bytes_length' to be >= 0.",
+                         CURRENT_FUNC);
+  }
+  Service::SendEmbedderEvent(isolate, stream_id, event_kind,
+                             bytes, bytes_length);
+  return Api::Success();
+}
+
+
 DART_EXPORT Dart_Handle Dart_TimelineDuration(const char* label,
                                               int64_t start_micros,
                                               int64_t end_micros) {