Version 3.27.10 (based on bleeding_edge revision r21414)

Implement Mirror object for Symbols (issue 3290).

Allow debugger to step into Map and Set forEach callbacks (issue 3341).

Fix ArrayShift hydrogen support (Chromium issue 374838).

Use SameValueZero for Map and Set (issue 1622).

Array Iterator next should check for own property.

Performance and stability improvements on all platforms.

git-svn-id: https://v8.googlecode.com/svn/trunk@21415 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Merge remote-tracking branch 'upstream/trunk' into trunk