Plug leaked string stream debug object cache in Isolate.

BUG=
R=danno@chromium.org

Review URL: https://codereview.chromium.org/18324007

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15411 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Fix compiler error about unused profiles_ field in ProfilerEventsProcessor.

BUG=
R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/18353002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15412 ce2b1a6d-e550-0410-aec6-3dcde31c8c00