roll: third_party/pigweed roll: gn

From git_revision:ab638bd7cbb9ac8468bf2fbe60c74ed4706a14a7
To git_revision:4a8016dc391553fa1644c0740cc04eaac844121e

Roll-Count: 1
GitWatcher: ignore
Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/272395
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Original-Revision: 8ffdd1514e11f6a6ba24b8620a12f922c28f6888

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: 7dd375c196e150..8ffdd1514e11f6
Roll-Count: 1
Roller-URL: https://cr-buildbucket.appspot.com/build/8721473119338450161
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Iea18cdc8ea715e7218ab3573de4cd18ff91f3776
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/examples/+/272432
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index 7dd375c..8ffdd15 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 7dd375c196e150e1da96fc9d768f3236b75fcbaf
+Subproject commit 8ffdd1514e11f6a6ba24b8620a12f922c28f6888