Let V8 know about the external memory owned by large StaticNodeList

Let V8 know about the external memory owned by large StaticNodeList

If a script allocates many large but short-lived StaticNodeList objects,
for instance by using querySelectorAll() in an inefficient way, memory
usage will balloon since V8's garbage collector won't realize that much
memory owned by it is being allocated, and thus doesn't run its GC.

Reporting external allocated memory to V8 is unnecessary overhead for
small objects, so only do it for objects larger than a limit.

BUG=342752
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=166937

[Jens Widell, 2014-02-11 15:52:24]

This is pretty much the same as https://codereview.chromium.org/64203002 except
for the limit that keeps us from reporting small node lists.

[jochen (gone - plz use gerrit), 2014-02-11 15:54:23]

lgtm

[Jens Widell, 2014-02-11 15:57:19]

The CQ bit was checked by jl@opera.com

[commit-bot: I haz the power, 2014-02-11 15:57:27]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jl@opera.com/154263007/1

[commit-bot: I haz the power, 2014-02-11 18:35:50]

Change committed as 166937