Themes: Full support for AOSP Volume Panel

- Recreate VolumePanel with theme enegine UiContext.
- Revert this https://gerrit.paranoidandroid.co/#/c/4375/ since we don't have
  the code with the panel they refer to. Just leave UiContext commented out, maybe
  we'll need that lately.

Signed-off-by: Carlo Savignano <stevewatersy@gmail.com>
Change-Id: Ifc9fd02ec4d263050b7d5f689935fa5e82095d26
Floating window: Fix possible NPE

Avoid possible NPE if app provides no interface such as pushbullet's
test notification & other apps which provide one.
PackageManagerService: Fix silly derp after 4.4.3 merge

Signed-off-by: Carlo Savignano <stevewatersy@gmail.com>
PackageManagerService: Fix concurrent access to shared state

Stop multiple threads from all calling add on the same HashMap.

Cleanup the use of a boolean flag by removing concurrent writes
to it.

Change-Id: I8d61fe7294dcb67ee7d0d7de88d90d2051c310e6