Add ignored controls metadata.

Ignored controls are optioned controls where the value
set by the user is tracked, but doesn't actually matter.

BUG: 30140438
Change-Id: I45819c3c6c855922418f76fd34309a44660fc3f0
TEST: unit tests pass
diff --git a/modules/camera/3_4/Android.mk b/modules/camera/3_4/Android.mk
index 01574b9..7b644c3 100644
--- a/modules/camera/3_4/Android.mk
+++ b/modules/camera/3_4/Android.mk
@@ -51,6 +51,7 @@
 v4l2_test_files := \
   metadata/control_test.cpp \
   metadata/fixed_property_test.cpp \
+  metadata/ignored_control_test.cpp \
   metadata/metadata_test.cpp \
   metadata/optioned_control_test.cpp \