ipcz: Add README.chromium

Fixed: 1352484
Change-Id: Ica27b33f393fe23458c6dfa4437c95957dba117c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4064982
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: Ken Rockot <rockot@google.com>
Cr-Commit-Position: refs/heads/main@{#1077545}
GitOrigin-RevId: 0680cfa741ea11caeb2cdc0f77da0bb03c5294eb
diff --git a/README.chromium b/README.chromium
new file mode 100644
index 0000000..0e5dc8a
--- /dev/null
+++ b/README.chromium
@@ -0,0 +1,12 @@
+Name: ipcz
+License: BSD
+License File: LICENSE
+Security Critical: Yes
+The //third_party/ipcz directory in the Chromium tree is the source-of-truth
+for this library. Patches here can here go through the same code review process
+as any other upstream Chromium CL.
+See README.md for an overview of what ipcz is.