Rename "extras exports" to "extras binding"

Rename "extras exports" to "extras binding"

R=yangguo@chromium.org, jochen@chromium.org
BUG=507133
LOG=Y

Committed: https://crrev.com/2dff84e66fd3c26a08aa214ee9a8d8d7cccb396c
Cr-Commit-Position: refs/heads/master@{#30053}

[domenic, 2015-08-05 19:05:23]

Technically a breaking change... in an API nobody is using, hopefully?

[Yang, 2015-08-06 05:51:59]

On 2015/08/05 19:05:23, domenic wrote:
> Technically a breaking change... in an API nobody is using, hopefully?

lgtm.

[jochen (gone - plz use gerrit), 2015-08-06 07:39:49]

lgtm

[domenic, 2015-08-06 22:55:53]

The CQ bit was checked by domenic@chromium.org

[commit-bot: I haz the power, 2015-08-06 22:56:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1275683002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1275683002/1

[commit-bot: I haz the power, 2015-08-06 23:52:54]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-06 23:53:08]

Patchset 1 (id:??) landed as
https://crrev.com/2dff84e66fd3c26a08aa214ee9a8d8d7cccb396c
Cr-Commit-Position: refs/heads/master@{#30053}