Dotcase: Only check for new notifications before displaying them

Rather than check for new notifications on every redraw, only check at
the beginning of each animation cycle (i.e., right before they're
about to be shown). This reduces notification checks from about twice
per second to about every 3 seconds.

Change-Id: Ia53de5bc24f3e41d33bfe5bc7c0f56b284e4d3e8
Merge "Dotcase: Only check for new notifications before displaying them" into cm-11.0