All classes are being migrated to BrowserCollectionObserver. Chromium changes: https://chromium.googlesource.com/chromium/src/+/2ebf7353bb2535b6121d1a26340d3f4e74046e42 commit 2ebf7353bb2535b6121d1a26340d3f4e74046e42 Author: Thomas Lukaszewicz <tluk@chromium.org> Date: Tue Apr 14 21:51:30 2026 -0700 [bedrock] Remove BrowserListObserver Bug: 431671320 Change-Id: Iff946bf520ab44049c855d91576ef53ca1916e00 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7744448 Reviewed-by: Qikai Zhong <qikaizhong@microsoft.com> Commit-Queue: Thomas Lukaszewicz <tluk@chromium.org> Cr-Commit-Position: refs/heads/main@{#1614935}