Introduces navigation keycodes.

These four new navigation keycodes are intended to be used to
navigate a tree hierarchy or list of items.  They should be used to
allow the user to advance forward or backward within a list of
sibling items, expand the currently selected item to navigate the
item's children, or back out from the current item to its parent
item or state.

Change-Id: I4781e9d7756ed00ca14d8d4c743da3cc0e68ea6c
diff --git a/include/input/InputEventLabels.h b/include/input/InputEventLabels.h
index 9aa7425..3962001 100644
--- a/include/input/InputEventLabels.h
+++ b/include/input/InputEventLabels.h
@@ -299,6 +299,10 @@
     DEFINE_KEYCODE(TV_MEDIA_CONTEXT_MENU),
     DEFINE_KEYCODE(TV_TIMER_PROGRAMMING),
     DEFINE_KEYCODE(HELP),
+    DEFINE_KEYCODE(NAVIGATE_PREVIOUS),
+    DEFINE_KEYCODE(NAVIGATE_NEXT),
+    DEFINE_KEYCODE(NAVIGATE_IN),
+    DEFINE_KEYCODE(NAVIGATE_OUT),
 
     { NULL, 0 }
 };