a6071e0880
Make one global thread pool instead of a thread pool for each eventhandler (i.e. isolate). Also: * Added handler function for thread pool tasks. * Added thread pool shutdown. * Added a simple test. R=ager@google.com BUG= TEST= Review URL: http://codereview.chromium.org//9112013 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@3079 260f80e4-7a28-3924-810f-c04153c831b5