[jsnar]

This doesn't make it safe -- consider a lower level library inside Chromium can be exploited when processing input data. Your chat app can be exploited by receiving a crafted image. This actually happened in image processing library and network library in Chromium.

[TheCoreh]

Sure, but the same can happen to whatever libraries you use on your native app. If anything Chromium is more likely to be patched, since there's a large entity interested in keeping it secure enough for accessing untrusted content.