Fix lifecycle of data reduction proxy objects in profile io data.
Move data_reduction_proxy_* field declarations from profile_impl_io_data.h
to profile_io_data.h, before chrome_network_delegate. This guarantees
that chrome_network_delegate is destroyed before the data reduction
proxy objects.
BUG=414806
Committed: https://chromium.googlesource.com/chromium/src/+/
d463f6b84e8a56d44904ec1418c99d7b47ea26dc
Review URL: https://codereview.chromium.org/
575143003
Cr-Commit-Position: refs/heads/master@{#296026}