Fix the flipping animation sometimes being played when pulling the quick
settings with two fingers.

Commit https://github.com/rascarlo/android_frameworks_base/commit/82d7868ebf2b9ea23d347e72c1b535459d1a8aec already tried to fix
this before, but was incomplete (and incorrect). The actual issue is
that on the first pointer down event, a 'peek' animation runs and
expands the notification panel by some pixels (on mako: 160). This
amount of pixels is significantly larger than the handle height (on
mako: 72). Depending on the timing between peek animation and the second
pointer down event, the flip animation would play (if animation already
revealed more than 72 pixels) or not.

Fix that by not playing the flip animation if only peeking, as the
actual panel content is not visible at that point anyway. Also remove
the previous incomplete fix in the process.
Pie controls: Fix flickering nav bar in full screen

On rare occasions the pie service will deadlock. When this
happens, full screen mode can no longer hide the
navigation bar, since it is masked out internally.

This commit switchs from a self cooked mask mechanism within
the WindowManager to the private flag
WindowManager.LayoutParams.PRIVATE_FLAG_FORCE_SHOW_NAV_BAR.

Note that this will avoid flickering when pie service get
stuck in the activation path, but it will not resolve the
deadlock.

Change-Id: I2b64867081b37d9d6070df8086975e4327d97f5d
Pie controls: Catching activation corner cases

As stated before there are still corner cases that may
deadlock pie controls.

This commit makes PieInputFilter respect ACTION_CANCEL,
simplifies monitoring mechanics in PieService and
fixes some corner cases in PieController that allowed that
activations got lost and thus pie controls got stuck.

Test case for PieController:
1) Enable pie controls
2) Enable top/bottom snap position for pie
2) Enable expanded desktop and check if it works
3) Disable expanded desktop
4) Lock your phone
5) Swipe from the top down/bottom up, as if you want to
   activate the pie from that position
6) Dismiss the notification tray and unlock your phone
   again
7) Enable extpanded desktop
8) Pie controls will no longer show up and
   "dumpsys pieservice" will show a active record.

Change-Id: Id9d2df6b2735a743eec2fd1ba809fd72be9474cc