Revert of Move GN grit scripts out of secondary tree.

Revert of Move GN grit scripts out of secondary tree. (patchset #1 id:1 of https://codereview.chromium.org/1317013002/ )

Reason for revert:
Apparently this was incorrect.

Original issue's description:
> Move GN grit scripts out of secondary tree.
>
> These build files were in the secondary tree because I thought tools/grit was DEPSed in. However, this directory is in the Chrome tree. The DEPSed-in directory is tools/grit/grit. Moving these files to the expected place will make things more clear.
>
> Committed: https://crrev.com/82d10f697a4268dd9ae0fffd8f3dfb1fb42901e5
> Cr-Commit-Position: refs/heads/master@{#345713}

TBR=thakis@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Committed: https://crrev.com/30327bc319a006e6c89a7b3cdf1fef86f05ec692
Cr-Commit-Position: refs/heads/master@{#345926}

[brettw, 2015-08-27 18:16:09]

Created Revert of Move GN grit scripts out of secondary tree.

[commit-bot: I haz the power, 2015-08-27 18:16:25]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1311133008/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1311133008/1

[commit-bot: I haz the power, 2015-08-27 18:17:39]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-27 18:18:15]

Patchset 1 (id:??) landed as
https://crrev.com/30327bc319a006e6c89a7b3cdf1fef86f05ec692
Cr-Commit-Position: refs/heads/master@{#345926}