Chrome Version: 64.0.3278.1
OS: all

What steps will reproduce the problem?
(1) Implement a UrlDataSource with AllowCaching() that returns false.
(2) Access the resources generated by the UrlDataSource multiple times (e.g. by setting it as a CSS background on an element multiple times).

What is the expected result?
It is expected that the renderer will fetch the resource every time, instead the resource is cached.

What happens instead?
The resource is cached in the renderer.

This can be fixed by changing URLDataManagerBackend::GetHeaders to set the "Cache-Control" header to "no-store" instead of "no-cache" as it is now (I can submit a patch).