[tracing] Avoid double-counting blink_gc free stats in memory-infra

[tracing] Avoid double-counting blink_gc free stats in memory-infra

Currently, when dumping blink_gc (Oilpan) memory, both the heap pages
and the freelists are scanned. Both of them report free bytes/objects.
At current state, this causes a dump of the following form:
blink_gc/thread_X/heaps/HeapName
blink_gc/thread_X/heaps/HeapName/pages    free_size=1M
blink_gc/thread_X/heaps/HeapName/buckets  free_size=1M

which causes the UI to infer the /HeapName has free_size=2M, which is
incorrect. This change forces the /HeapName dump to override the
free_{size,count} attributes in order to match the HeapName/pages dump.

BUG=490087
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=197987

[Primiano Tucci (use gerrit), 2015-06-29 11:08:57]

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

[haraken, 2015-06-29 11:55:29]

LGTM

https://codereview.chromium.org/1217793002/diff/1/Source/platform/heap/Heap.cpp
File Source/platform/heap/Heap.cpp (right):

https://codereview.chromium.org/1217793002/diff/1/Source/platform/heap/Heap.c...
Source/platform/heap/Heap.cpp:283: // eqauel to the free_size of the sum of its
heap pages.

equal

[Primiano Tucci (use gerrit), 2015-06-29 13:12:26]

The CQ bit was checked by primiano@chromium.org

[Primiano Tucci (use gerrit), 2015-06-29 13:12:27]

The patchset sent to the CQ was uploaded after l-g-t-m from haraken@chromium.org
Link to the patchset: https://codereview.chromium.org/1217793002/#ps20001
(title: "typo")

[commit-bot: I haz the power, 2015-06-29 13:12:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1217793002/20001

[commit-bot: I haz the power, 2015-06-29 14:13:55]

Committed patchset #2 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=197987