Refactor keys and queries in datastore service and implementation.

filter/count/count.go

Index: filter/count/count.go
diff --git a/filter/count/count.go b/filter/count/count.go
index 2a7b2dd0da85d9eacaaa50d2238c5d2fbf629f36..d3ff220497037071f56fb9a17492b29266e0f48a 100644
--- a/filter/count/count.go
+++ b/filter/count/count.go
@@ -40,10 +40,12 @@ func (e *Entry) String() string {
 // this API. It's Successes+Errors.
 func (e *Entry) Total() int64 { return int64(e.Successes()) + int64(e.Errors()) }
 
+// Successes returns the number of successful invocations for this Entry.
 func (e *Entry) Successes() int {
 	return e.successes.get()
 }
 
+// Errors returns the number of unsuccessful invocations for this Entry.
 func (e *Entry) Errors() int {
 	return e.errors.get()
 }