Upstream commit: https://webrtc.googlesource.com/src/+/ef95b20fbc59fbe33c066201e84ec51fda7fc762 Move safe_conversions.h to webrtc namespace Bug: webrtc:42232595 Change-Id: I4145233e74fc684539d493423cafe142159fe8ff Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/378720 Reviewed-by: Harald Alvestrand <hta@webrtc.org> Commit-Queue: Evan Shrubsole <eshr@webrtc.org> Cr-Commit-Position: refs/heads/main@{#43973} Differential Revision: https://phabricator.services.mozilla.com/D243977