[Chromecast] Replace 'fontconfig' GN target with dynamic dependency.

[Chromecast] Replace 'fontconfig' GN target with dynamic dependency.

Chromecast needs to be able to optionally use //third_party/fontconfig
instead of system headers. This CL acheives parity with the GYP build
for this feature:
https://code.google.com/p/chromium/codesearch#chromium/src/build/linux/system.gyp&l=748

BUG=516899
Committed: https://crrev.com/17e5ce7ff587612814565e8fa2d737e76feb3e56
Cr-Commit-Position: refs/heads/master@{#350711}

[slan, 2015-09-23 18:01:15]

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

[commit-bot: I haz the power, 2015-09-23 18:03:30]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1366653003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1366653003/1

[commit-bot: I haz the power, 2015-09-23 18:03:31]

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

[commit-bot: I haz the power, 2015-09-23 18:03:32]

Dry run: No L-G-T-M from a valid reviewer yet. Only full committers are
accepted.
Even if an L-G-T-M may have been provided, it was from a non-committer,
_not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[slan, 2015-09-23 21:44:16]

slan@chromium.org changed reviewers:
+ brettw@chromium.org, dpranke@chromium.org, halliwell@chromium.org,
spang@chromium.org

[slan, 2015-09-23 21:44:16]

Chromecast would like to depend on //third_party/fontconfig for internal ARM
builds, rather than provide headers.

+halliwell@ for visibility.

[Dirk Pranke, 2015-09-24 19:29:48]

lgtm.

[slan, 2015-09-24 19:33:09]

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

[commit-bot: I haz the power, 2015-09-24 19:39:06]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1366653003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1366653003/20001

[brettw, 2015-09-24 19:43:13]

lgtm

[commit-bot: I haz the power, 2015-09-24 19:53:08]

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

[commit-bot: I haz the power, 2015-09-24 19:53:09]

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

[slan, 2015-09-24 21:51:03]

The CQ bit was checked by slan@chromium.org

[slan, 2015-09-24 21:51:03]

The patchset sent to the CQ was uploaded after l-g-t-m from
dpranke@chromium.org, brettw@chromium.org
Link to the patchset: https://codereview.chromium.org/1366653003/#ps40001
(title: "Correct dep in //chrome/browser/chromeos")

[commit-bot: I haz the power, 2015-09-24 21:51:34]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1366653003/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1366653003/40001

[commit-bot: I haz the power, 2015-09-25 00:04:53]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-09-25 00:05:57]

Patchset 3 (id:??) landed as
https://crrev.com/17e5ce7ff587612814565e8fa2d737e76feb3e56
Cr-Commit-Position: refs/heads/master@{#350711}