Clean up popup window positioning
Clean up popup window positioning

- Only move the popup above the anchor when necessary
- Adjust the y position when displaying the popup above the anchor
  rather than changing the popup gravity
- Reduce popup height if it's still too large after repositioning

Bug: 27819843
Change-Id: I1ecc235816a61b9431568a34d3116e286e092c11

xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base