Remove redundant activation threshold for incremental marking.

Remove redundant activation threshold for incremental marking.

The minimum allocation limit already enforces this constraint for normal GCs.

GCs triggered by the memory reducer and external limit should work for all heap sizes.

BUG=chromium:552305
LOG=NO

Committed: https://crrev.com/e28e4d5f52852e2f14facc37a02069b6bfc82c4e
Cr-Commit-Position: refs/heads/master@{#31921}

[ulan, 2015-11-10 15:23:43]

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

[ulan, 2015-11-10 15:23:44]

PTAL

[Hannes Payer (out of office), 2015-11-10 16:41:54]

On 2015/11/10 15:23:44, ulan wrote:
> PTAL

Lgtm, but watch out for benchmarks.

[ulan, 2015-11-10 16:55:35]

The CQ bit was checked by ulan@chromium.org

[commit-bot: I haz the power, 2015-11-10 16:55:41]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1418293006/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1418293006/1

[commit-bot: I haz the power, 2015-11-10 17:14:10]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-10 17:14:26]

Patchset 1 (id:??) landed as
https://crrev.com/e28e4d5f52852e2f14facc37a02069b6bfc82c4e
Cr-Commit-Position: refs/heads/master@{#31921}

[ulan, 2015-11-17 13:12:51]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1456523002/ by ulan@chromium.org.

The reason for reverting is: Regression in thread_times.key_idle_power_cases
(crbug.com/555153).