Clean up output of heap object tracing

Clean up output of heap object tracing

BUG=

Committed: https://crrev.com/068a6afb4494e12c9ad6bc93f1e6eae792dbc2d8
Cr-Commit-Position: refs/heads/master@{#27929}

[ulan, 2015-04-17 09:09:21]

ulan@chromium.org changed reviewers:
+ hpayer@chromium.org

[ulan, 2015-04-17 09:09:21]

PTAL

[Hannes Payer (out of office), 2015-04-17 09:10:21]

lgtm

[ulan, 2015-04-17 09:14:47]

The CQ bit was checked by ulan@chromium.org

[commit-bot: I haz the power, 2015-04-17 09:15:01]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1097683002/1

[commit-bot: I haz the power, 2015-04-17 09:25:16]

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

[commit-bot: I haz the power, 2015-04-17 09:25:17]

Try jobs failed on following builders:
  v8_linux_gcc_compile_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_gcc_compile_rel/bu...)

[ulan, 2015-04-18 08:34:48]

The CQ bit was checked by ulan@chromium.org

[ulan, 2015-04-18 08:34:49]

The patchset sent to the CQ was uploaded after l-g-t-m from hpayer@chromium.org
Link to the patchset: https://codereview.chromium.org/1097683002/#ps20001
(title: "Fix compile error")

[commit-bot: I haz the power, 2015-04-18 08:35:01]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1097683002/20001

[commit-bot: I haz the power, 2015-04-18 09:21:20]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-04-18 09:21:39]

Patchset 2 (id:??) landed as
https://crrev.com/068a6afb4494e12c9ad6bc93f1e6eae792dbc2d8
Cr-Commit-Position: refs/heads/master@{#27929}