Re-roll GN to 326666 and fix GN-related bugs.

Re-roll GN to 326666 and fix GN-related bugs.

Fix bugs related to the latest GN roll.

1) the new GN binary will return an error if you pass it
a file it doesn't know anything about in 'gn refs'.

2) for some reason with the new GN binary we're triggering a
code path in gyp_flag_compare.py that wasn't running before,
and that code path was busted.

TBR=brettw@chromium.org
BUG=
CQ_EXTRA_TRYBOTS=tryserver.chromium.linux:linux_chromium_gn_dbg;tryserver.chromium.mac:mac_chromium_gn_rel,mac_chromium_gn_dbg;tryserver.chromium.win:win8_chromium_gn_rel

Committed: https://crrev.com/0b3b788227da8865280c19eb2aadddfe03ff71b4
Cr-Commit-Position: refs/heads/master@{#326736}

[Dirk Pranke, 2015-04-24 01:57:25]

dpranke@chromium.org changed reviewers:
+ horo@chromium.org

[horo, 2015-04-24 02:14:37]

lgtm

[Dirk Pranke, 2015-04-24 02:16:52]

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

[commit-bot: I haz the power, 2015-04-24 02:17:19]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1109453002/20001

[Dirk Pranke, 2015-04-24 03:26:31]

The CQ bit was unchecked by dpranke@chromium.org

[Dirk Pranke, 2015-04-24 03:26:33]

The CQ bit was checked by dpranke@chromium.org

[commit-bot: I haz the power, 2015-04-24 03:26:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1109453002/20001

[commit-bot: I haz the power, 2015-04-24 03:38:22]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-04-24 03:39:11]

Patchset 2 (id:??) landed as
https://crrev.com/0b3b788227da8865280c19eb2aadddfe03ff71b4
Cr-Commit-Position: refs/heads/master@{#326736}