Use depfiles for mojom generation.

Use depfiles for mojom generation.

Currently, if foo.mojom imports bar.mojom and bar.mojom changes,
foo.mojom will not be regenerated. If the change to bar.mojom changes
which traits headers should be included by foo.mojom.cc by adding or
removing a typemapped type, this can cause compile failures. This CL
fixes this by generating a depfile for each mojom generation step so
changing any mojoms imported by a particular mojom cause the bindings
for that mojom to be regenerated.

BUG=652404
Review-Url: https://codereview.chromium.org/2747653002
Cr-Commit-Position: refs/heads/master@{#456513}
Committed: https://chromium.googlesource.com/chromium/src/+/8e4878fdb12d295c90bbfe58adf3d87016561695

[Sam McNally, 2017-03-13 05:37:09]

The CQ bit was checked by sammc@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-03-13 05:37:32]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Sam McNally, 2017-03-13 05:58:18]

sammc@chromium.org changed reviewers:
+ yzshen@chromium.org

[commit-bot: I haz the power, 2017-03-13 07:08:34]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-03-13 07:08:35]

Dry run: Try jobs failed on following builders:
  linux_chromium_chromeos_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[Sam McNally, 2017-03-13 07:09:35]

The CQ bit was checked by sammc@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-03-13 07:09:45]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-03-13 07:47:07]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-03-13 07:47:08]

Dry run: This issue passed the CQ dry run.

[yzshen1, 2017-03-13 17:01:38]

lgtm

[Sam McNally, 2017-03-13 22:32:46]

The CQ bit was checked by sammc@chromium.org

[commit-bot: I haz the power, 2017-03-13 22:34:11]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-03-13 22:45:24]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1489444366563350, "parent_rev":
"80ceeee5bc83abc038e4e8cc4e0e8d0fbc710576", "commit_rev":
"8e4878fdb12d295c90bbfe58adf3d87016561695"}

[commit-bot: I haz the power, 2017-03-13 22:46:10]

Description was changed from

==========
Use depfiles for mojom generation.

Currently, if foo.mojom imports bar.mojom and bar.mojom changes,
foo.mojom will not be regenerated. If the change to bar.mojom changes
which traits headers should be included by foo.mojom.cc by adding or
removing a typemapped type, this can cause compile failures. This CL
fixes this by generating a depfile for each mojom generation step so
changing any mojoms imported by a particular mojom cause the bindings
for that mojom to be regenerated.

BUG=652404
==========

to

==========
Use depfiles for mojom generation.

Currently, if foo.mojom imports bar.mojom and bar.mojom changes,
foo.mojom will not be regenerated. If the change to bar.mojom changes
which traits headers should be included by foo.mojom.cc by adding or
removing a typemapped type, this can cause compile failures. This CL
fixes this by generating a depfile for each mojom generation step so
changing any mojoms imported by a particular mojom cause the bindings
for that mojom to be regenerated.

BUG=652404

Review-Url: https://codereview.chromium.org/2747653002
Cr-Commit-Position: refs/heads/master@{#456513}
Committed:
https://chromium.googlesource.com/chromium/src/+/8e4878fdb12d295c90bbfe58adf3...
==========

[commit-bot: I haz the power, 2017-03-13 22:46:11]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/8e4878fdb12d295c90bbfe58adf3...