Use Unique<Map> in CompareMap.

Use Unique<Map> in CompareMap.

BUG=
R=verwaest@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=16843

[titzer, 2013-09-19 12:27:36]

Now you get your asserts!

[Toon Verwaest, 2013-09-19 13:15:03]

lgtm

[titzer, 2013-09-19 15:33:45]

On 2013/09/19 13:15:03, Toon Verwaest wrote:
> lgtm

Had to hack the tests to deal with the new ASSERT in the constructor of
Unique<T>. PTAL if you don't mind.

[Toon Verwaest, 2013-09-19 16:49:44]

weird semicolon placement. LGTM :)

[titzer, 2013-09-19 17:03:10]

Committed patchset #2 manually as r16843 (presubmit successful).