Move functions useful for crypto test into their own file

More refactoring in advance of work on bug.

Bug: 36029169
Test: compiles.
Change-Id: Ic4cdd4761e4c2b11a3ddca5c3bbc4d5e42fac9d4
diff --git a/Android.mk b/Android.mk
index e92955f..4971ec7 100644
--- a/Android.mk
+++ b/Android.mk
@@ -158,7 +158,10 @@
 LOCAL_TIDY := true
 LOCAL_TIDY_FLAGS := $(common_local_tidy_flags)
 LOCAL_TIDY_CHECKS := $(common_local_tidy_checks)
-LOCAL_SRC_FILES:= secdiscard.cpp
+LOCAL_SRC_FILES:= \
+    FileDeviceUtils.cpp \
+    secdiscard.cpp \
+
 LOCAL_MODULE:= secdiscard
 LOCAL_SHARED_LIBRARIES := libbase
 LOCAL_CFLAGS := $(vold_cflags)