Themes: PhoneWindowManager UI context on demand

Creating the UI context in init causes some elements
like the power menu to not theme correctly. This solution follows
the same pattern as VolumePanel.

Change-Id: I5c12f9a3bc8f5fe8d96ef2775b840926a6c35e28

Conflicts:
	policy/src/com/android/internal/policy/impl/PhoneWindowManager.java
Themes: Theme immersive mode cling.

Change-Id: I5521b93f69e859c40cfd62eb4a367562200074e9

Conflicts:
	policy/src/com/android/internal/policy/impl/ImmersiveModeConfirmation.java
Themes: Avoid compiling icon packs every boot

Change-Id: I51c7effdd4592a302f457822a05cbebee6cde06b

Conflicts:
	services/java/com/android/server/pm/PackageManagerService.java
Cleanup app->{theme1,theme2...} mapping on uninstall

Change-Id: I24b43e8817db1927d5b43fcf7ad3340269d046ea
HeadsUp: Fix dismiss on back key press.

Change-Id: Ia213aeba114d153f5561622a2bea884963f3d8a1
BaseStatusBar: Dismiss heads up on backpress.

Change-Id: I5b6191657cf0b74d825eb653a6e82c33e0527aad