Synchronize store buffer processing and concurrent sweeping.

BUG=
R=jarin@chromium.org, mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/227533006

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20582 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Return 0 as maximal amount of physical memory if there is no limit.

That's what the comment says should happen, and what Heap's ctor
expects.

BUG=none
LOG=n
R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/226113006

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20583 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Compile fix for NaCL

TBR=mstarzinger@chromium.org
BUG=none
LOG=n

Review URL: https://codereview.chromium.org/228953002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20584 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Use OrderedHashTables as the backing store of JSSet and JSMap

This also deletes ObjectHashSet as it's no longer used.

BUG=v8:1793
LOG=N
R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/225183009

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20585 ce2b1a6d-e550-0410-aec6-3dcde31c8c00