'step in' with a watch sometimes opens empty editor and crashes adapter

[roblourens]

• Add a watch
• Hit a breakpoint
• step in somewhere

Doesn't always happen but often it will cause an empty editor to be opened, with a number as the title.

The problem is that we are doing an evaluate immediately after sending Chrome the stepIn request, and we actually step in to the evaluate code. I think the timing of the watch's evaluate request is different now in 1.9 which is why this didn't happen before. Stuff happens in this order:

stepIn request
resumed event
evaluate request
paused event

I think the only way to fix this will be to delay an evaluate if it comes immediately after a step, 'immediately' being 100ms or so.