Accounts for the removal of the previous UI guideline pages,
which is where most of this new content came from.
Also update figure to add xxhdpi and remove ldpi,
and include 2x version, because ya know, irony.
Change-Id: Ia37ef1a65bdf9c4173a323ae37fffe03b53a6fcf
These new URLs are dummies that are handled by a redirect rule for
all /downloads/... paths, that points to http://commondatastorage.googleapis.com/androiddevelopers/
Using this redirect allows us to change the storage location of the download assets in the future.
Change-Id: I0dc6ecc1a6898f1256ba4c9ff90b619366e47629
