Roll gn from c4748415f12a to 85f62c164c82

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Cq-Include-Trybots: luci.dart.try:dart-sdk-linux-try;luci.dart.try:dart-sdk-mac-try;luci.dart.try:dart-sdk-mac-arm64-try;luci.dart.try:dart-sdk-win-try
Change-Id: I7442d309b509c704ea6fe227c6cbda3e7b6c3f60
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/441722
Commit-Queue: Ryan Macnak <[email protected]>
Reviewed-by: Ryan Macnak <[email protected]>
Reviewed-by: Alexander Markov <[email protected]>

Author: DEPS Autoroller

DEPS

@@ -78,7 +78,7 @@ vars = {
   "clang_version": "git_revision:8c7a2ce01a77c96028fe2c8566f65c45ad9408d3",
 
   # https://chrome-infra-packages.appspot.com/p/gn/gn
-  "gn_version": "git_revision:c4748415f12ac92d2781608b8b84fcc0e33e5ff9",
+  "gn_version": "git_revision:85f62c164c829442fb662f6aa1243c02bcc47155",
 
   "reclient_version": "re_client_version:0.178.0.5ee9d3e8-gomaip",
   "download_reclient": True,