[tracing] Add light dumps in the V8 dump provider

[tracing] Add light dumps in the V8 dump provider

This CL updates the V8 dump provider to dump only totals of the heap when a
light dump is requested.

BUG=499731
Committed: https://crrev.com/2888a24fd1d63a4c2afd9102d72be2f36d581ba5
Cr-Commit-Position: refs/heads/master@{#342471}

[ssid, 2015-08-05 10:30:42]

ssid@chromium.org changed reviewers:
+ petrcermak@chromium.org

[ssid, 2015-08-05 10:30:43]

PTAL

[petrcermak, 2015-08-05 10:52:28]

LGTM!

Thanks,
Petr

[petrcermak, 2015-08-05 10:57:39]

One more nit: s/in/to the/ in the title and first line.

[ssid, 2015-08-07 09:37:56]

ssid@chromium.org changed reviewers:
+ jochen@chromium.org

[ssid, 2015-08-07 09:37:56]

+jochen PTAL. Small patch for V8. Thanks

[jochen (gone - plz use gerrit), 2015-08-07 09:42:05]

lgtm

[ssid, 2015-08-07 12:58:27]

The CQ bit was checked by ssid@chromium.org

[ssid, 2015-08-07 12:58:27]

The patchset sent to the CQ was uploaded after l-g-t-m from jochen@chromium.org,
petrcermak@chromium.org
Link to the patchset: https://codereview.chromium.org/1266003003/#ps20001
(title: "Rebase.")

[commit-bot: I haz the power, 2015-08-07 12:58:49]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-08-07 12:58:49]

This CL has an open dependency (Issue 1282453002 Patch 80001). Please resolve
the dependency and try again.

[ssid, 2015-08-07 23:01:20]

The CQ bit was checked by ssid@chromium.org

[commit-bot: I haz the power, 2015-08-07 23:02:51]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1266003003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1266003003/20001

[commit-bot: I haz the power, 2015-08-07 23:08:51]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-08-07 23:09:33]

Patchset 2 (id:??) landed as
https://crrev.com/2888a24fd1d63a4c2afd9102d72be2f36d581ba5
Cr-Commit-Position: refs/heads/master@{#342471}