[tracing] Fix malloc accounting in memory-infra

[tracing] Fix malloc accounting in memory-infra

Currently the malloc dump provider is reporting the total virtual
size as official "size" (the one plotted in the tracks) and the
allocated_objects as a child.
This is not fully correct, as the heap is not always necessarily
used and, more importantly, creates some funky behavior when
discounting the trace overehad.
This change moves the outer heap size to its own property, so that
the actual |uordblocks| becomes the size plotted on the track.

BUG=495628, 467112
Committed: https://crrev.com/db8a28cf1603950a2dedda3329d01285a3e317cd
Cr-Commit-Position: refs/heads/master@{#334812}

[Primiano Tucci (use gerrit), 2015-06-17 10:32:25]

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

[Primiano Tucci (use gerrit), 2015-06-17 10:32:25]

PTAL

[petrcermak, 2015-06-17 10:34:41]

LGTM. We just have to make sure that we are consistent across allocators.

Thanks,
Petr

[Primiano Tucci (use gerrit), 2015-06-17 10:35:16]

The CQ bit was checked by primiano@chromium.org

[commit-bot: I haz the power, 2015-06-17 10:35:50]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1191893002/1

[commit-bot: I haz the power, 2015-06-17 11:58:18]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-06-17 11:59:12]

Patchset 1 (id:??) landed as
https://crrev.com/db8a28cf1603950a2dedda3329d01285a3e317cd
Cr-Commit-Position: refs/heads/master@{#334812}