Set lower allocation limit in idle notification only if no GC happend recently.

Set lower allocation limit in idle notification only if no GC happend recently.

BUG=475674
LOG=n

Committed: https://crrev.com/35e3489e8f70c7ad5973324ad3cfa4ab27059ab4
Cr-Commit-Position: refs/heads/master@{#28506}

[Hannes Payer (out of office), 2015-05-20 07:46:13]

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

[ulan, 2015-05-20 10:37:06]

lgtm.

Let's land this to fix perf regression. Later we can generalize this to use
decaying function for allocation_limit.

[Hannes Payer (out of office), 2015-05-20 10:58:22]

The CQ bit was checked by hpayer@chromium.org

[commit-bot: I haz the power, 2015-05-20 10:58:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1143113002/20001

[commit-bot: I haz the power, 2015-05-20 10:59:49]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-05-20 11:00:01]

Patchset 2 (id:??) landed as
https://crrev.com/35e3489e8f70c7ad5973324ad3cfa4ab27059ab4
Cr-Commit-Position: refs/heads/master@{#28506}

[Michael Achenbach, 2015-05-20 12:48:39]

A revert of this CL (patchset #2 id:20001) has been created in
https://codereview.chromium.org/1145113003/ by machenbach@chromium.org.

The reason for reverting is: [Sheriff] MSAN not happy:
http://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20arm64%20-%20s....