Always enable lazy sweeping.

Always enable lazy sweeping.

This turns on lazy sweeping for enable_oilpan=0.

Lazy/incremental sweeping reduces GC pause times by having the
garbage collector perform its marking and processing of live
objects together with a minimal amount of sweeping of finalizable
objects before returning. The remaining heap regions to be swept
up and finalized are then handled incrementally as part of
heap allocation requests. Amortizing that sweeping cost rather
than taking a longer GC "stop the world" pause in one go.

Lazy sweeping is enabled with Oilpan always on (enable_oilpan=1);
this extends it to also be for the Oilpan GCs that run on trunk
(where enable_oilpan=0).

R=haraken
BUG=480837
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=198095

[haraken, 2015-06-30 08:01:24]

haraken@chromium.org changed reviewers:
+ haraken@chromium.org, oilpan-reviews@chromium.org

[haraken, 2015-06-30 08:01:24]

Let's try this now. LGTM.

[sof, 2015-06-30 19:04:53]

The CQ bit was checked by sigbjornf@opera.com

[commit-bot: I haz the power, 2015-06-30 19:06:27]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1219613002/1

[commit-bot: I haz the power, 2015-06-30 20:14:30]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=198095