Remove ToAggregation

Instead of having the temporary bridge, fix the user's code.

Also contains some godoc improvements.

stats/view/aggregation.go

@@ -21,23 +21,18 @@ package view
 type AggType int
 
 const (
-	// AggTypeNone represents no aggregation. Reserved for future use.
-	AggTypeNone AggType = iota
-	// AggTypeCount represents the count aggregation, See Count().
-	AggTypeCount
-	// AggTypeSum represents the sum aggregation, See Sum().
-	AggTypeSum
-	// AggTypeMean represents the mean aggregation, see Mean()
-	AggTypeMean
-	// AggTypeDistribution represents a distribution aggregation, see Distribution().
-	AggTypeDistribution
+	AggTypeNone         AggType = iota // no aggregation; reserved for future use.
+	AggTypeCount                       // the count aggregation, see Count.
+	AggTypeSum                         // the sum aggregation, see Sum.
+	AggTypeMean                        // the mean aggregation, see Mean.
+	AggTypeDistribution                // the distribution aggregation, see Distribution.
 )
 
 // Aggregation represents a data aggregation method. Use one of the functions:
 // Count, Sum, Mean, or Distribution to construct an Aggregation.
 type Aggregation struct {
 	Type    AggType   // Type is the AggType of this Aggregation.
-	Buckets []float64 // Buckets are the bucket endpoints if this Aggregation represents a distribution, see: Distribution().
+	Buckets []float64 // Buckets are the bucket endpoints if this Aggregation represents a distribution, see Distribution.
 
 	newData func() AggregationData
 }
@@ -71,13 +66,6 @@ func Count() *Aggregation {
 	return aggCount
 }
 
-// SumAggregation indicates that data collected and aggregated
-// with this method will be summed up.
-// For example, accumulated request bytes can be aggregated by using
-// SumAggregation.
-// Deprecated: Use the Sum function to construct.
-type SumAggregation struct{}
-
 // Sum indicates that data collected and aggregated
 // with this method will be summed up.
 // For example, accumulated request bytes can be aggregated by using

stats/view/view.go

@@ -47,7 +47,7 @@ type View struct {
 }
 
 // Deprecated: Use &View{}.
-func New(name, description string, keys []tag.Key, measure stats.Measure, agg ToAggregation) (*View, error) {
+func New(name, description string, keys []tag.Key, measure stats.Measure, agg *Aggregation) (*View, error) {
 	if measure == nil {
 		panic("measure may not be nil")
 	}
@@ -56,27 +56,10 @@ func New(name, description string, keys []tag.Key, measure stats.Measure, agg To
 		Description: description,
 		TagKeys:     keys,
 		Measure:     measure,
-		Aggregation: agg.ToAggregation(),
+		Aggregation: agg,
 	}, nil
 }
 
-// ToAggregation is a temporary bridge for SumAggregation to Aggregation. It is
-// needed to support existing external uses of SumAggregation in cloud.google.com/go
-// and should be removed once those are removed.
-type ToAggregation interface {
-	ToAggregation() *Aggregation
-}
-
-// ToAggregation returns Sum.
-func (s SumAggregation) ToAggregation() *Aggregation {
-	return Sum()
-}
-
-// ToAggregation returns the receiver.
-func (a *Aggregation) ToAggregation() *Aggregation {
-	return a
-}
-
 // WithName returns a copy of the View with a new name. This is useful for
 // renaming views to cope with limitations placed on metric names by various
 // backends.