This patch is introducing a way to grab heap stats.

This patch is introducing a way to grab heap stats.
The idea is to monitor the heap regulary and track each object in the heap.
With this data we will be able do draw heap usage diagram.
Where X is time and Y is the number of objects.

BUG=none
TEST=HeapSnapshotObjectsStats

Review URL: https://chromiumcodereview.appspot.com/10049002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11302 ce2b1a6d-e550-0410-aec6-3dcde31c8c00