Merge changes Idc4c2c14,Ibea016c6,I49ab58c3,Id911d405,I0f17dc5f, ... into nyc-mr1-dev

* changes:
  Improved the transition when clicking on the last notification
  Fixed a bug that could lead to an empty notification
  Removed contentDescriptions that hindered accessibility usability
  Fixes a bug where setting a null bigLargeIcon would not clear it
  Fixed the transition of the background of the notifications
  Fixed a bug where the notification would fade out in a ugly way