Version 3.27.16 (based on bleeding_edge revision r21574)

Allow microtasks to throw exceptions and handle them gracefully (Chromium issue 371566).

Performance and stability improvements on all platforms.

git-svn-id: https://v8.googlecode.com/svn/trunk@21576 ce2b1a6d-e550-0410-aec6-3dcde31c8c00