Update ChromeSurveyController comment about keeping enums.xml in sync

BUG=842692

Change-Id: I7b8b2b6b259c9b18706f294e99a4530729a21d13
Reviewed-on: https://chromium-review.googlesource.com/1155367
Commit-Queue: Theresa <twellington@chromium.org>
Reviewed-by: Mark Pearson <mpearson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579164}
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/survey/ChromeSurveyController.java b/chrome/android/java/src/org/chromium/chrome/browser/survey/ChromeSurveyController.java
index f2e3a465..f3e4ba7 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/survey/ChromeSurveyController.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/survey/ChromeSurveyController.java
@@ -63,7 +63,8 @@
 
     /**
      * Reasons that the user was rejected from being selected for a survey
-     *  Note: these values must match the SurveyFilteringResult enum in enums.xml.
+     * Note: these values cannot change and must match the SurveyFilteringResult enum in enums.xml
+     * because they're written to logs.
      */
     @IntDef({FilteringResult.SURVEY_INFOBAR_ALREADY_DISPLAYED,
             FilteringResult.FORCE_SURVEY_ON_COMMAND_PRESENT,