This is a resubmit of codereview.chromium.org/13818012 with the following modifications:
- src/x64/code-stubs-x64.cc for changes specific to Win64   calling conventions.
- src/sampler.cc for Native Client support

BUG=v8:2614

Committed: https://code.google.com/p/v8/source/detail?r=14491

Review URL: https://codereview.chromium.org/14305029

Patch from Brad Chen <bradchen@google.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14494 ce2b1a6d-e550-0410-aec6-3dcde31c8c00