Forward Port: Volume button seek on screen off [1/2]

PS : Fix the short press event type

Change-Id: Id55a1240a133b5144502fced862bae040b390662

Conflicts:
	core/java/android/provider/Settings.java
	policy/src/com/android/internal/policy/impl/PhoneWindowManager.java

Conflicts:
	core/java/android/provider/Settings.java
	policy/src/com/android/internal/policy/impl/PhoneWindowManager.java