Include xxhdpi densities in theme engine.

Change-Id: If1730b0be3d8d786d44004e24e72d91f3921d198
Hide navigation area and increase max notification icons for devices with hardware keys.

Change-Id: I591daeca90dc35fbbc23d4b2e27b94000c2c78b5
Use navigation_key_width_tablet for lights out views.

Change-Id: I77d61439e6269bd599a8d2923480632a007b6bf0
Merge "Hide navigation area and increase max notification icons for devices with hardware keys." into jellybean-mr1
Merge "Use navigation_key_width_tablet for lights out views." into jellybean-mr1