Log visibility change for DialogCreatable in Settings.

Bug: 30681529
Test: adb logcat -b events | egrep "(sysui_|notification_)"
Test: make RunSettingsRoboTests
Change-Id: I51754d258ba1ddfae24323681f21cd02de4dbb4e

src/com/android/settings/EncryptionInterstitial.java

@@ -259,6 +259,14 @@ public class EncryptionInterstitial extends SettingsActivity {
             }
         }
 
+        @Override
+        public int getDialogMetricsCategory(int dialogId) {
+            if (dialogId == ACCESSIBILITY_WARNING_DIALOG) {
+                return MetricsEvent.DIALOG_ENCRYPTION_INTERSTITIAL_ACCESSIBILITY;
+            }
+            return 0;
+        }
+
         private void setRequirePasswordState(boolean required) {
             mPasswordRequired = required;
         }