Status Bar - Wrap visible content in containers

* Implement `onMeasure` in NotificationIconContainer so that we can use
  `wrap_content` on it.
* Wrap the status bar left and right contents in containers with
  `wrap_content`

By wrapping the visible content in containers, we can easily extract the
visible bounds without having to programmatically calculate bounds.

Change-Id: Iebb6c0ddbb767262b0858466db99ea44938f82d3
Merged-In: I07f7a8f4e362b8f4cb32fc196ee1c011498435f7
Fixes: 238410585
Test: Manually