Don't use windowOutsetBottom for insets, depend on display padding only.

I am not sure if this is the correct approach to the problem. Right now
we are reporting double chin (60 vs 30). The reason for this is that
we setDisplayPadding from Clockwork Home activity (bottom=30) and add
windowOutsetBottom.

We use display padding to set surface frame size (320x320) and both
outset bottom and display padding for inset. I think we should use only
one of these. I decided to go with display padding, because that's
what was suggested to me the last time I visited this. I removed
the dependency on windowOutsetBottom altogether.

However, I don't feel confident this is the correct way to do this.
We depend on Home activity to send the display padding now to get
the correct result, so wallpapers behind other activities will not
work correctly.

Maybe instead of setting display padding from the outside, the
windowOutsetBottom should be added to display padding bottom for the
purpose of calculating surface frame and generating insets.

Advice on what is the right approach here would be greatly appreciated.

Bug: 19881056
Change-Id: Ifb655528d8f85ef01d942bf1e64e8b08475689ca