Changing Size to SizeOfObjects in GetHeapSpaceStatistics api.

Changing Size to SizeOfObjects in GetHeapSpaceStatistics api.

This CL changes GetHeapSpaceStatistics api to return SizeOfObjects()
instead of Size(). SizeOfObjects is the required field and is
consistent with GetHeapStatistics api.

BUG=476013
LOG=N

Committed: https://crrev.com/0be81a43eaf83e3b08143a8deb0115c7632c0e9f
Cr-Commit-Position: refs/heads/master@{#28080}

[ssid, 2015-04-24 14:32:46]

ssid@chromium.org changed reviewers:
+ hpayer@chromium.org, primiano@chromium.org

[ssid, 2015-04-24 14:33:24]

1 line change. PTAL.
Thanks

[Hannes Payer (out of office), 2015-04-27 13:28:58]

lgtm

[ssid, 2015-04-27 13:29:35]

The CQ bit was checked by ssid@chromium.org

[commit-bot: I haz the power, 2015-04-27 13:29:43]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1095393005/1

[commit-bot: I haz the power, 2015-04-27 14:00:30]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-27 14:00:45]

Patchset 1 (id:??) landed as
https://crrev.com/0be81a43eaf83e3b08143a8deb0115c7632c0e9f
Cr-Commit-Position: refs/heads/master@{#28080}