Adding total available size of heap in v8 isolate memory dump provider.

Adding total available size of heap in v8 isolate memory dump provider.

The total available size is now returned by GetHeapStatistics api.
This CL uses the value in the dump provider to show the value in
other_spaces segment of the memory dump.

BUG=481504
Committed: https://crrev.com/9ad94e6e06201059c08d67b9d9ab4a30a766b541
Cr-Commit-Position: refs/heads/master@{#329303}

[ssid, 2015-05-08 17:08:41]

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

[ssid, 2015-05-08 17:08:41]

PTAL.

[Primiano Tucci (use gerrit), 2015-05-11 09:15:47]

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

[Primiano Tucci (use gerrit), 2015-05-11 09:15:47]

LGTM thanks.

+jochen for an OWNER stamp

[jochen (gone - plz use gerrit), 2015-05-11 23:31:40]

lgtm

[Primiano Tucci (use gerrit), 2015-05-11 23:58:42]

The CQ bit was checked by primiano@chromium.org

[commit-bot: I haz the power, 2015-05-12 00:01:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1129403003/1

[commit-bot: I haz the power, 2015-05-12 01:01:29]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-05-12 01:02:20]

Patchset 1 (id:??) landed as
https://crrev.com/9ad94e6e06201059c08d67b9d9ab4a30a766b541
Cr-Commit-Position: refs/heads/master@{#329303}

[ssid, 2015-05-12 16:19:31]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1134233002/ by ssid@chromium.org.

The reason for reverting is: The HeapStatistics::total_available_size returned
by v8 API doesn't return the correct value right now. It only returns the sum of
available size of 4 spaces only. So, this should land after the API gets fixed..