[Isolates] Make MarkCompactCollector::IterateLiveObject to treat callback as a method of the class.

[Isolates] Make MarkCompactCollector::IterateLiveObject to invoke its callback as a member of MarkCompactCollector, eliminating the need for those callbacks to be static. This, in turn, makes them able to use MarkCompactCollector::heap_ variable instead of pulling the Heap pointer via Isolate::Current().

Committed: http://code.google.com/p/v8/source/detail?r=5444

[Dmitry Titov, 2010-09-10 22:20:38]

I'm getting a small but measurable improvement on this (~1.5% locally on
string-add)

[Vitaly Repeshko, 2010-09-10 22:27:18]

LGTM

http://codereview.chromium.org/3329024/diff/1/3
File src/mark-compact.h (right):

http://codereview.chromium.org/3329024/diff/1/3#newcode365
src/mark-compact.h:365: typedef int
(MarkCompactCollector::*LiveObjectCallback)(HeapObject* obj);
Typedefs are supposed to be among the first things declared in a class body.

[Dmitry Titov, 2010-09-10 22:32:13]

Updated, landed. Thanks!