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

Signed-off-by: San Mehat <san@google.com>
diff --git a/CommandListener.h b/CommandListener.h
index e6fa805..7d4560f 100644
--- a/CommandListener.h
+++ b/CommandListener.h
@@ -48,6 +48,12 @@
         int runCommand(SocketClient *c, int argc, char ** argv);
     };
 
+    class StorageCmd : public VoldCommand {
+    public:
+        StorageCmd();
+        virtual ~StorageCmd() {}
+        int runCommand(SocketClient *c, int argc, char ** argv);
+    };
 };
 
 #endif