Improve GN header checker, make //ui pass.

Improve GN header checker, make "check" on //ui/* pass.

I went through and made "gn check //ui/*" pass, and did a lot of enhancements for the bugs I found.

Fixes a big bug in the header checker where it did not consider direct private dependencies to be OK from a header include perspective. However, private deps only change things when there are intermediate targets. This patch marks direct deps OK, and changes the variable names from is_public to is_permitted (since it may not actually be public).

Allow includes to be permitted if any target allows the include, rather than all of them. This happens if multiple targets have the same file as sources.

Strip the generated file directory from the beginning of sources. Previously, this was only for outputs (since typically they're included assuming the root gen dir is on the path). This comes up when an action generates a file, and then it's put into a source set (which we do a lot). This change allows a public dependency on the source set to count for header include purposes.

Track public/private deps in the dependency path finder so the error message can show which deps are private that break the chain. This was really helpful when tracking down errors.

Add deps and public deps to the build to make check pass.

R=scottmg@chromium.org

Committed: https://chromium.googlesource.com/chromium/src/+/0380637c0085884d209fbbcaf0f0b0871fac162a

[brettw, 2014-09-18 19:58:29]

brettw@chromium.org changed reviewers:
+ jamesr@chromium.org

[brettw, 2014-09-18 22:01:08]

brettw@chromium.org changed reviewers:
+ scottmg@chromium.org
- jamesr@chromium.org

[brettw, 2014-09-18 22:01:09]

Apparently James is on vacation. Can you look at this Scott?

[scottmg, 2014-09-18 22:33:52]

lgtm with those tests, or without if you don't think they add anything.

https://codereview.chromium.org/584683002/diff/20001/tools/gn/header_checker.h
File tools/gn/header_checker.h (right):

https://codereview.chromium.org/584683002/diff/20001/tools/gn/header_checker....
tools/gn/header_checker.h:41: bool is_public;
should this be is_permitted too? i'm a little confused by the A -> P -> C test

https://codereview.chromium.org/584683002/diff/20001/tools/gn/header_checker_...
File tools/gn/header_checker_unittest.cc (right):

https://codereview.chromium.org/584683002/diff/20001/tools/gn/header_checker_...
tools/gn/header_checker_unittest.cc:128: EXPECT_EQ(HeaderChecker::ChainLink(&p,
true), chain[1]);
hm, no i guess is_public for ChainLink makes sense.

https://codereview.chromium.org/584683002/diff/20001/tools/gn/header_checker_...
tools/gn/header_checker_unittest.cc:131: 
since the iteration depends on discarding disallowed paths before finding an
allowed one, maybe adding a test that has the private before/after.

i.e.

A - B - C
  \   /
    P

vs.
    Q
  /   \
A - B - C
  \   /
    P

https://codereview.chromium.org/584683002/diff/20001/tools/gn/header_checker_...
tools/gn/header_checker_unittest.cc:140: EXPECT_TRUE(is_permitted);
Maybe a test that

A -> B -> C -> D

is right too, when B->C is private. That is, A -> D disallowed, but chain[0] is
public.

[brettw, 2014-09-19 17:03:42]

I added some more testing. Not quite all of what you were suggesting, but should
be good enough I think.

[brettw, 2014-09-19 17:03:47]

The CQ bit was checked by brettw@chromium.org

[commit-bot: I haz the power, 2014-09-19 17:04:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/584683002/40001

[commit-bot: I haz the power, 2014-09-19 17:08:08]

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

[commit-bot: I haz the power, 2014-09-19 17:08:10]

Try jobs failed on following builders:
  mac_gpu on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/mac_gpu/builds/58296)

[scottmg, 2014-09-19 17:10:45]

lgtm

[brettw, 2014-09-19 19:25:19]

The CQ bit was checked by brettw@chromium.org

[brettw, 2014-09-19 19:25:22]

The CQ bit was unchecked by brettw@chromium.org

[commit-bot: I haz the power, 2014-09-19 21:26:35]

Patchset 4 (id:??) landed as
https://crrev.com/0380637c0085884d209fbbcaf0f0b0871fac162a
Cr-Commit-Position: refs/heads/master@{#295783}

[brettw, 2014-09-19 21:26:36]

Committed patchset #4 (id:60001) manually as 0380637.