[whatwg] HTML extension for system idle detection.

[timeless]

So, i don't have a place to stick this...

In working on the n900, we've added features which generally break
javascript activity if the user is not using the web page.

We've chosen (or perhaps have been forced) to do this because battery
life is generally considered more important than other properties.

We're also discovering that people worried about battery life
strenuously object to waking up the processor or radio after a delay.

If a client server application wants to know if the user is idle, the
algorithm is this:
If the client hasn't sent a message indicating the user is not idle in
the last <pick interval>, then the user is idle.

Anything that relies on the client to decide if the user is idle is
just wasting our cpu cycles and radio cycles. And as a result, the
user agent is likely to terminate the task anyway.

This is implementation experience. The patches we've used to enable
these behaviors will of course be available with the launch of the
n900 for people to review.