Revert of Revert of Remove now obsolete checkdeps copy

Revert of Revert of Remove now obsolete checkdeps copy (https://codereview.chromium.org/320043002/)

Reason for revert:
should be safe to land now

Original issue's description:
> Revert of Remove now obsolete checkdeps copy (https://codereview.chromium.org/307333003/)
> 
> Reason for revert:
> Still referenced from blink
> 
> Original issue's description:
> > Remove now obsolete checkdeps copy
> > 
> > BUG=none
> > R=brettw@chromium.org
> > 
> > Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=275419
> 
> TBR=brettw@chromium.org
> NOTREECHECKS=true
> NOTRY=true
> BUG=none
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=275482

TBR=brettw@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=none

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=276734

[jochen (gone - plz use gerrit), 2014-06-12 17:29:34]

Created Revert of Revert of Remove now obsolete checkdeps copy

[jochen (gone - plz use gerrit), 2014-06-12 17:38:33]

The CQ bit was checked by jochen@chromium.org

[commit-bot: I haz the power, 2014-06-12 17:40:58]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jochen@chromium.org/334743002/1

[commit-bot: I haz the power, 2014-06-12 17:44:27]

Change committed as 276734

[Feng Qian, 2014-06-14 06:52:26]

On 2014/06/12 17:44:27, I haz the power (commit-bot) wrote:
> Change committed as 276734

clang-builder seems using tools/checkdeps/.
https://uberchromegw.corp.google.com/i/clank/builders/clang-builder/builds/4973