Add a BUILD.gn for some //chrome/browser/lifetime files.

This CL adds a source_set for termination_notification.cc/.h which
unblocks modularization for some extension APIs.

AX-Relnotes: n/a.
Bug: 353332589
Change-Id: Id5ce5af346ce53d43fa614af03953bd28bfcb03d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6484772
Commit-Queue: Erik Chen <[email protected]>
Auto-Submit: David Bertoni <[email protected]>
Reviewed-by: Erik Chen <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1450934}
diff --git a/chrome/browser/ui/apps/BUILD.gn b/chrome/browser/ui/apps/BUILD.gn
index 3f3708f..21a0af3f 100644
--- a/chrome/browser/ui/apps/BUILD.gn
+++ b/chrome/browser/ui/apps/BUILD.gn
@@ -36,6 +36,7 @@
     "//chrome/browser/devtools",
     "//chrome/browser/favicon",
     "//chrome/browser/file_system_access",
+    "//chrome/browser/lifetime:termination_notification",
     "//chrome/browser/media/webrtc",
     "//chrome/browser/picture_in_picture",
     "//chrome/browser/profiles:profile",