Syncing external/chromium with chromium release 61029, part 1

This is our current version, all the deleted files do not exist upstream,
and are not used by us.

Deleting files that are not code from net/. Also removing the flip
directory since the whole folder is removed upstream and we are not
using it.

Change-Id: I5758ea8d8b3daa25c9182500c2f581de28ac7984
59 files changed