Add missing patch methods to dart2js implementation of timeline

sdk/lib/_internal/js_runtime/lib/developer_patch.dart

Index: sdk/lib/_internal/js_runtime/lib/developer_patch.dart
diff --git a/sdk/lib/_internal/js_runtime/lib/developer_patch.dart b/sdk/lib/_internal/js_runtime/lib/developer_patch.dart
index 2ff405ca014e001c46b61345236d1057d1abbb6f..e13f5806ffcf778e03d90286699648c9dd58afd1 100644
--- a/sdk/lib/_internal/js_runtime/lib/developer_patch.dart
+++ b/sdk/lib/_internal/js_runtime/lib/developer_patch.dart
@@ -60,3 +60,18 @@ void _reportCompleteEvent(int start,
                           String argumentsAsJson) {
   // TODO.
 }
+
+@patch
+int _getNextAsyncId() {
+  return 0;
+}
+
+@patch
+void _reportTaskEvent(int start,
+                      int taskId,
+                      String phase,
+                      String category,
+                      String name,
+                      String argumentsAsJson) {
+ // TODO.
+}