Add a comment on the spell checker framework

Change-Id: Ibd826d68074d8524cbeaae296ce483f8b10c3d07
diff --git a/services/java/com/android/server/TextServicesManagerService.java b/services/java/com/android/server/TextServicesManagerService.java
index 6587c41..0964767 100644
--- a/services/java/com/android/server/TextServicesManagerService.java
+++ b/services/java/com/android/server/TextServicesManagerService.java
@@ -154,6 +154,8 @@
                         mContext, mSpellCheckerList, mSpellCheckerMap, mSettings);
                 // TODO: Update for each locale
                 SpellCheckerInfo sci = getCurrentSpellChecker(null);
+                // If no spell checker is enabled, just return. The user should explicitly
+                // enable the spell checker.
                 if (sci == null) return;
                 final String packageName = sci.getPackageName();
                 final int change = isPackageDisappearing(packageName);