Reland "[heap] No leakage of mark-compact.h outside of heap."

Reland "[heap] No leakage of mark-compact.h outside of heap."

The revert of the original change in question did not recover
regressions, which allows us to reland this cleanup after all.

This reverts commit 871529b4d86c406b4139129f138d88177a728a09.

R=hpayer@chromium.org

Committed: https://crrev.com/e494bcca7e9391a0d593046dfd7b341f659fafd1
Cr-Commit-Position: refs/heads/master@{#31214}

[Hannes Payer (out of office), 2015-10-12 14:49:23]

lgtm

[Michael Starzinger, 2015-10-12 14:58:37]

The CQ bit was checked by mstarzinger@chromium.org

[commit-bot: I haz the power, 2015-10-12 14:58:48]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1393773004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1393773004/1

[commit-bot: I haz the power, 2015-10-12 15:20:18]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-12 15:20:44]

Patchset 1 (id:??) landed as
https://crrev.com/e494bcca7e9391a0d593046dfd7b341f659fafd1
Cr-Commit-Position: refs/heads/master@{#31214}