Update Skia GYP and GN configs to read source lists from opts.gypi.

Update Skia GYP and GN configs to read source lists from opts.gypi.

Add me to OWNERS too to shut up the presubmits.

I tested this locally on OS X / x86-64.  Relying on the bots for the rest.

BUG=

Committed: https://crrev.com/9116f9f9b648f2983f156c77aca116a207b7d3fb
Cr-Commit-Position: refs/heads/master@{#313365}

[mtklein_C, 2015-01-27 17:15:33]

mtklein@chromium.org changed reviewers:
+ reed@google.com

[reed1, 2015-01-27 18:23:15]

awesome!
lgtm

[mtklein, 2015-01-27 18:24:02]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2015-01-27 18:25:04]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/859393004/1

[commit-bot: I haz the power, 2015-01-27 19:05:17]

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

[commit-bot: I haz the power, 2015-01-27 19:05:17]

Try jobs failed on following builders:
  linux_chromium_compile_dbg_32_ng on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

Try jobs failed on following builders:
  linux_chromium_compile_dbg_32_ng on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[mtklein, 2015-01-27 20:21:49]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2015-01-27 20:23:16]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/859393004/20001

[commit-bot: I haz the power, 2015-01-27 21:52:17]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-01-27 21:53:18]

Patchset 2 (id:??) landed as
https://crrev.com/9116f9f9b648f2983f156c77aca116a207b7d3fb
Cr-Commit-Position: refs/heads/master@{#313365}