Fix debuggersupport=off build after r17184 and r18149.

Fix debuggersupport=off build after r17184 and r18149.

R=rossberg@chromium.org
BUG=

Committed: https://code.google.com/p/v8/source/detail?r=20193

[kennyluck, 2014-03-23 17:04:04]

I think we might want to make most use of ENABLE_DEBUGGER_SUPPORT to just a flag
conditional to reduce the chance of breaking this yet again in the future.

[rossberg, 2014-03-24 07:53:51]

lgtm

[kennyluck, 2014-03-24 08:40:13]

The CQ bit was checked by kanghao.lkh@alibaba-inc.com

[kennyluck, 2014-03-24 09:00:20]

On 2014/03/24 08:40:13, kennyluck wrote:
> The CQ bit was checked by mailto:kanghao.lkh@alibaba-inc.com

Meh. I am not sure what I did (git cl set-commit) was sensible. If you need to
stop it, please help!

[kennyluck, 2014-03-24 12:01:57]

The CQ bit was unchecked by kanghao.lkh@alibaba-inc.com

[kennyluck, 2014-03-24 12:02:03]

The CQ bit was checked by kanghao.lkh@alibaba-inc.com

[kennyluck, 2014-03-24 12:03:28]

The CQ bit was unchecked by kanghao.lkh@alibaba-inc.com

[kennyluck, 2014-03-24 12:10:06]

On 2014/03/24 12:03:28, kennyluck wrote:
> The CQ bit was unchecked by mailto:kanghao.lkh@alibaba-inc.com

Meh. I guess commit queue just doesn't work for non-committers (but it doesn't
give me any notice......). rossberg, can you land this for me?

[rossberg, 2014-03-24 13:04:41]

Committed patchset #1 manually as r20193 (presubmit successful).