Replace build_angle.gyp with angle.gyp.

Replace build_angle.gyp with angle.gyp.

The final step in switching the angle gyp file will be to remove
the temporary angle_gyp variable.

BUG=415983
Committed: https://crrev.com/424be9e0114b848c022d07f843f803c87be56be7
Cr-Commit-Position: refs/heads/master@{#297450}

[Jamie Madill, 2014-09-30 14:33:06]

jmadill@chromium.org changed reviewers:
+ piman@chromium.org

[Jamie Madill, 2014-09-30 14:33:24]

PTAL... a small change that touches a lot of files.

[piman, 2014-09-30 15:10:33]

lgtm

[Jamie Madill, 2014-09-30 17:56:49]

The CQ bit was checked by jmadill@chromium.org

[commit-bot: I haz the power, 2014-09-30 17:57:48]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/614053003/1

[commit-bot: I haz the power, 2014-09-30 18:02:43]

Committed patchset #1 (id:1) as c2c8a8199bb132d0c088e3184d7a7d603b4cce22

[commit-bot: I haz the power, 2014-09-30 18:03:47]

Patchset 1 (id:??) landed as
https://crrev.com/424be9e0114b848c022d07f843f803c87be56be7
Cr-Commit-Position: refs/heads/master@{#297450}