Added automatic debug break for processing debugger commands

A new stack guard break flag DEBUGCOMMAND has been introduced. This is used to signal debug break due to debugger commands available in the queue for processing. If a stack guard break happens with this flag and not the DEBUGBREAK flag the no debug break event is generated and execution is resumed automatically when all debugger commands in the queue has been processed.

This makes it possible to remote debuggers to just add commands to the queue without having to request a break as well. As soon as any JavaScript executes the debugger commands will be processed and the response send to the remote debugger.

Currently hide this behind a flag (--debugger-auto-break) as the current command line debugger in Chrome is not designed for this new behaviour, whereas the new Chrome developer tools will use it.

Committed: http://code.google.com/p/v8/source/detail?r=1508

[Mads Ager (chromium), 2009-03-13 13:14:57]

LGTM