Support slicing by chain.

BUG: b/73975181

Test: statsd test
Change-Id: I913ae0f68ff21ed0703bb5da9c60d3eaa3bf5981
diff --git a/cmds/statsd/src/HashableDimensionKey.h b/cmds/statsd/src/HashableDimensionKey.h
index 4cfed88..6f4941f 100644
--- a/cmds/statsd/src/HashableDimensionKey.h
+++ b/cmds/statsd/src/HashableDimensionKey.h
@@ -122,17 +122,14 @@
 /**
  * Creating HashableDimensionKeys from FieldValues using matcher.
  *
- * This function may make modifications to the Field if the matcher has Position=LAST or ANY in
- * it. This is because: for example, when we create dimension from last uid in attribution chain,
+ * This function may make modifications to the Field if the matcher has Position=FIRST,LAST or ALL
+ * in it. This is because: for example, when we create dimension from last uid in attribution chain,
  * In one event, uid 1000 is at position 5 and it's the last
  * In another event, uid 1000 is at position 6, and it's the last
  * these 2 events should be mapped to the same dimension.  So we will remove the original position
  * from the dimension key for the uid field (by applying 0x80 bit mask).
  */
 bool filterValues(const std::vector<Matcher>& matcherFields, const std::vector<FieldValue>& values,
-                  std::vector<HashableDimensionKey>* output);
-// This function is used when there is at most one output dimension key. (no ANY matcher)
-bool filterValues(const std::vector<Matcher>& matcherFields, const std::vector<FieldValue>& values,
                   HashableDimensionKey* output);
 
 /**