The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8586921e08baafc1209e66223d0642d6246094b9

commit 8586921e08baafc1209e66223d0642d6246094b9
Author: twifkak <twifkak@chromium.org>
Date: Wed Jan 11 21:57:58 2017

Add revalidation_only option to precache config.

When specified, resources are only fetched over the network if they have
an existing cache entry with revalidation headers. This serves as a
lower-bound approximation of the efficacy of a client-only wifi precache
mechanism, as it is limited to URLs that are only on the client AND in
the manifests.

BUG= 679533 

Review-Url: https://codereview.chromium.org/2614403003
Cr-Commit-Position: refs/heads/master@{#442999}

[modify] https://crrev.com/8586921e08baafc1209e66223d0642d6246094b9/components/precache/core/precache_fetcher.cc
[modify] https://crrev.com/8586921e08baafc1209e66223d0642d6246094b9/components/precache/core/precache_fetcher.h
[modify] https://crrev.com/8586921e08baafc1209e66223d0642d6246094b9/components/precache/core/precache_fetcher_unittest.cc
[modify] https://crrev.com/8586921e08baafc1209e66223d0642d6246094b9/components/precache/core/proto/precache.proto

Your change meets the bar and is auto-approved for M56. Please go ahead and merge the CL manually. Please contact milestone owner if you have questions.
Owners: amineer@(clank), cmasso@(bling), gkihumba@(cros), bustamante@(desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/dfc79d6a2692eede9e158d649e42a8e9567b65f0

commit dfc79d6a2692eede9e158d649e42a8e9567b65f0
Author: Devin Mullins <twifkak@google.com>
Date: Thu Jan 12 22:42:19 2017

Add revalidation_only option to precache config.

When specified, resources are only fetched over the network if they have
an existing cache entry with revalidation headers. This serves as a
lower-bound approximation of the efficacy of a client-only wifi precache
mechanism, as it is limited to URLs that are only on the client AND in
the manifests.

BUG= 679533 

Review-Url: https://codereview.chromium.org/2614403003
Cr-Commit-Position: refs/heads/master@{#442999}
(cherry picked from commit 8586921e08baafc1209e66223d0642d6246094b9)

Review-Url: https://codereview.chromium.org/2623263006 .
Cr-Commit-Position: refs/branch-heads/2924@{#748}
Cr-Branched-From: 3a87aecc31cd1ffe751dd72c04e5a96a1fc8108a-refs/heads/master@{#433059}

[modify] https://crrev.com/dfc79d6a2692eede9e158d649e42a8e9567b65f0/components/precache/core/precache_fetcher.cc
[modify] https://crrev.com/dfc79d6a2692eede9e158d649e42a8e9567b65f0/components/precache/core/precache_fetcher.h
[modify] https://crrev.com/dfc79d6a2692eede9e158d649e42a8e9567b65f0/components/precache/core/precache_fetcher_unittest.cc
[modify] https://crrev.com/dfc79d6a2692eede9e158d649e42a8e9567b65f0/components/precache/core/proto/precache.proto