Why 2 different logos?

[Roul P.]

Why they are 2 different logos used in Chromium? One is more dark bluish and the other is (from version 11) is more light blue.
Both are actual used (anywhere) and in the actual branch:

https://cs.chromium.org/chromium/src/chrome/app/theme/chromium/product_logo_256.png

and the second (vector version, from version11)

https://storage.googleapis.com/chrome-infra-public/logo/chromium.svg
https://cs.chromium.org/chromium/src/chrome/app/theme/chromium/product_logo.ai

https://cs.chromium.org/chromium/src/chrome/app/theme/chromium/chromium.ai