kmarshall: PTAL. It appears that all of the archive, package and runner generation steps all have this issue (based on selectively disabling each in the test.gni and rules.gni files).

`ninja gn_all -d explain` might (or might not) help illuminate what's not getting built/stamped.

Re #2: Aha, perfect - that immediately showed that we have some errant |depfile| values listed, for steps which don't actually create depfiles! 

Also from review discussion, it looks like we ought to have https://cs.chromium.org/chromium/build/scripts/slave/recipe_modules/chromium_tests/chromium_linux.py?q=ninja_confirm_noop&sq=package:chromium&dr=C&l=20 added to the 'Fuchsia' ones in the 'chromium_apply_config' list so we don't regress this again too.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d3f8d267ec975458cd5adfb951f38bb5c019ad24

commit d3f8d267ec975458cd5adfb951f38bb5c019ad24
Author: Wez <wez@chromium.org>
Date: Fri Feb 16 06:53:23 2018

Remove errant |depfile| entries on archive and script rules.

The action rules had |depfile| set, but did not actually create a file,
resulting in the steps being re-run even in no-op builds.

Bug:  812352 
Change-Id: Ia1aa862b2ec96cb5a0304339c861f564bc77b34a
Reviewed-on: https://chromium-review.googlesource.com/920794
Commit-Queue: Wez <wez@chromium.org>
Reviewed-by: Scott Graham <scottmg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#537239}
[modify] https://crrev.com/d3f8d267ec975458cd5adfb951f38bb5c019ad24/build/config/fuchsia/package.gni
[modify] https://crrev.com/d3f8d267ec975458cd5adfb951f38bb5c019ad24/build/config/fuchsia/rules.gni

tikuta@ has a CL in review to have the bots enforce this, so assigning to them. :)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/tools/build/+/b9e6eb82bf2263ded7bf8239a58a25764dea23b3

commit b9e6eb82bf2263ded7bf8239a58a25764dea23b3
Author: Takuto Ikuta <tikuta@google.com>
Date: Fri Feb 16 21:37:08 2018

Enable confirm noop step in Fuchsia buildbot

Bug:  812352 
Change-Id: I702f2fa757039a2d3556ff18f74d6be4136cf7e3
Reviewed-on: https://chromium-review.googlesource.com/923921
Reviewed-by: Scott Graham <scottmg@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: Takuto Ikuta <tikuta@google.com>

[modify] https://crrev.com/b9e6eb82bf2263ded7bf8239a58a25764dea23b3/scripts/slave/recipe_modules/chromium_tests/chromium_linux.py