Debugger: remove debug command API.

Debugger: remove debug command API.

Instead, please use v8::Isolate::RequestInterrupt to synchronize
to the main thread.

R=yurys@chromium.org
API=Removed v8::Debug::DebugBreakForCommand
LOG=Y

Committed: https://crrev.com/8e723e98929b68c87ce39ff9f5c2d136a2ed8a46
Cr-Commit-Position: refs/heads/master@{#27625}

[Yang, 2015-03-25 13:26:09]

Please take a look. I plan to land this one week after
https://codereview.chromium.org/1038603002/

[yurys, 2015-03-25 13:35:48]

lgtm

[Yang, 2015-04-07 10:44:24]

The CQ bit was checked by yangguo@chromium.org

[commit-bot: I haz the power, 2015-04-07 10:44:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1036863002/1

[commit-bot: I haz the power, 2015-04-07 10:59:56]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-04-07 10:59:57]

Try jobs failed on following builders:
  v8_linux_nodcheck_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_nodcheck_rel/build...)

[Yang, 2015-04-07 11:58:33]

The CQ bit was checked by yangguo@chromium.org

[Yang, 2015-04-07 11:58:34]

The patchset sent to the CQ was uploaded after l-g-t-m from yurys@chromium.org
Link to the patchset: https://codereview.chromium.org/1036863002/#ps20001
(title: "fix test")

[commit-bot: I haz the power, 2015-04-07 11:58:41]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1036863002/20001

[commit-bot: I haz the power, 2015-04-07 12:21:39]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-04-07 12:21:53]

Patchset 2 (id:??) landed as
https://crrev.com/8e723e98929b68c87ce39ff9f5c2d136a2ed8a46
Cr-Commit-Position: refs/heads/master@{#27625}