Add ninja dependency reference to gen written files.

Add ninja dependency reference to gen written files.

For example, if one or more of the <blah>.tmp files is removed, even as part of an entire hierarchy/subtree currently the build fails because ninja does not know how to re-make it.

While it works, I don't like this hack.  It asserts that the build needs to be rewritten if files generated by "gn gen" are out of date.

While true, that's not really the best expression in the ninja 'language' of what's really happening.

It is a nice small change though.

BUG=469621
TEST=Build time only. See https://code.google.com/p/chromium/issues/detail?id=469621#c3

Committed: https://crrev.com/d82b2317e6bd619236ca7de934b341e7b32e7380
Cr-Commit-Position: refs/heads/master@{#337873}

[Peter Mayo, 2015-07-02 22:12:15]

https://codereview.chromium.org/1222693002/diff/1/build/toolchain/cros/BUILD.gn
File build/toolchain/cros/BUILD.gn (right):

https://codereview.chromium.org/1222693002/diff/1/build/toolchain/cros/BUILD....
build/toolchain/cros/BUILD.gn:34: 
Bah - remove this.

[Peter Mayo, 2015-07-02 22:30:53]

petermayo@chromium.org changed reviewers:
+ brettw@chromium.org, dpranke@chromium.org

[Peter Mayo, 2015-07-02 22:30:53]

PTAL.
It seems this change doesn't change the existing unittests (they still pass).
It's not immediately obvious how best to add unittests for this, suggestions
welcome.


Contrast with https://codereview.chromium.org/1220223002/

[brettw, 2015-07-06 21:29:40]

LGTM with minor tweaks

https://codereview.chromium.org/1222693002/diff/20001/tools/gn/function_write...
File tools/gn/function_write_file.cc (right):

https://codereview.chromium.org/1222693002/diff/20001/tools/gn/function_write...
tools/gn/function_write_file.cc:117: // Track how to recreate this file, since
we write it a gen time.
Can you put a blank line above this?

https://codereview.chromium.org/1222693002/diff/20001/tools/gn/function_write...
tools/gn/function_write_file.cc:119: // but an addition of this file to the
output of the gn rule that writes it.
can you append something like "so if this file is missing the build will be
re-run."

[Peter Mayo, 2015-07-06 22:09:00]

https://codereview.chromium.org/1222693002/diff/20001/tools/gn/function_write...
File tools/gn/function_write_file.cc (right):

https://codereview.chromium.org/1222693002/diff/20001/tools/gn/function_write...
tools/gn/function_write_file.cc:117: // Track how to recreate this file, since
we write it a gen time.
On 2015/07/06 21:29:39, brettw wrote:
> Can you put a blank line above this?

Done.

https://codereview.chromium.org/1222693002/diff/20001/tools/gn/function_write...
tools/gn/function_write_file.cc:119: // but an addition of this file to the
output of the gn rule that writes it.
On 2015/07/06 21:29:39, brettw wrote:
> can you append something like "so if this file is missing the build will be
> re-run."

Done.

[Peter Mayo, 2015-07-08 18:41:13]

The CQ bit was checked by petermayo@chromium.org

[Peter Mayo, 2015-07-08 18:41:14]

The patchset sent to the CQ was uploaded after l-g-t-m from brettw@chromium.org
Link to the patchset: https://codereview.chromium.org/1222693002/#ps40001
(title: "Improve comments")

[commit-bot: I haz the power, 2015-07-08 18:42:49]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1222693002/40001

[commit-bot: I haz the power, 2015-07-08 18:59:59]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-07-08 19:01:02]

Patchset 3 (id:??) landed as
https://crrev.com/d82b2317e6bd619236ca7de934b341e7b32e7380
Cr-Commit-Position: refs/heads/master@{#337873}