vold: Refactor Processkiller and add command to return users of a mount point

Signed-off-by: San Mehat <san@google.com>
diff --git a/Android.mk b/Android.mk
index d90b399..9036f78 100644
--- a/Android.mk
+++ b/Android.mk
@@ -20,7 +20,7 @@
                   Volume.cpp                           \
                   DirectVolume.cpp                     \
                   logwrapper.c                         \
-                  ProcessKiller.c                      \
+                  Process.cpp                          \
                   geom_mbr_enc.c                       \
                   Fat.cpp                              \
                   Loop.cpp                             \