Add support for ClassIntrospector and TypeDeclarationsResolver forwarding

Change-Id: If897fe6f1eef2f3976986935bd90fbc0417a8be6
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/228724
Auto-Submit: Jake Macdonald <jakemac@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Johnni Winther <johnniwinther@google.com>

https://dart.googlesource.com/sdk/+/26d9cb5146e7553ab7cc6d696e425793506b511f
diff --git a/commits.json b/commits.json
index d111cfb..35747b0 100644
--- a/commits.json
+++ b/commits.json
@@ -1,5 +1,5 @@
 {
   "external/github.com/flutter/engine":"2ebc3d3e442d5b70d5755fdfa19787af8d2c645b",
   "external/github.com/flutter/flutter":"8017883a5dfd13d709c4bd04d617f54a6cb2271f",
-  "sdk":"b449fe4398f5188a54694bfcea8f2dc8f645e45e"
+  "sdk":"26d9cb5146e7553ab7cc6d696e425793506b511f"
 }
\ No newline at end of file