Fix MMAP_LIST in dumps by deep-heap-profile again.

Fix MMAP_LIST in dumps by deep-heap-profile again.

All bucket_ids in MMAP_LIST were wrongly 0.
This change fixes the issue by changing the scope and the oparation order.

It also adds a description for SnapshotMaps().

BUG=181517
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=191619

[Dai Mikurube (NOT FULLTIME), 2013-03-29 08:26:20]

Hi Alexander,

Sorry, the previous TBR fix was too incorrect, so reverted in
https://codereview.chromium.org/13259003/. :(

It's a better fix, and it adds a description for the complicated function
SnapshotMasp().

Could you take a look?

[Alexander Potapenko, 2013-03-29 16:52:20]

Sorry, I'm kinda lost in this code right now. Let me try to better comprehend it
before giving an LGTM

[willchan no longer on Chromium, 2013-03-29 16:59:48]

On 2013/03/29 16:52:20, Alexander Potapenko wrote:
> Sorry, I'm kinda lost in this code right now. Let me try to better comprehend
it
> before giving an LGTM

I'm going to let glider handle this, but can you update the changelist
description to explain what was broken about the previous fix and how you're
addressing it in this one?

[Dai Mikurube (NOT FULLTIME), 2013-03-29 17:29:32]

Ah, yes, it needs a better commit log.  Updated it.  Thanks!

[Dai Mikurube (NOT FULLTIME), 2013-04-01 10:47:15]

(a reminder just because we had a weekend. :))

[Alexander Potapenko, 2013-04-01 13:51:12]

LGTM
Sorry for this having taken too long.

[Dai Mikurube (NOT FULLTIME), 2013-04-01 15:18:22]

Thank you!

[commit-bot: I haz the power, 2013-04-01 15:18:28]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/dmikurube@chromium.org/13299002/9001

[commit-bot: I haz the power, 2013-04-01 17:34:24]

Change committed as 191619