When Data Saver is enabled, Chrome provides a Save-Data client hint and a JS attribute saveData as part of the NetworkInformation API. That causes some sites to reduce the amount of data they transfer to Chrome. This data savings should probably be reported to Data Saver Home.

We need to decide if this makes sense as a part of feature and then, if so, implement the code. We'll need to come up with a way of estimating that savings, e.g., by permanently running a holdback group.