[processor/cumulativetodelta] Remove stable gate (#20717)

* Remove stable gate

* changelog

* Go mod tidy

.chloggen/ctd-remove-gate.yaml

@@ -0,0 +1,16 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: breaking
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: cumulativetodeltaprocessor
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Removes stable `processor.cumulativetodeltaprocessor.EnableHistogramSupport` feature gate. Setting this gate will cause an error.
+
+# One or more tracking issues related to the change
+issues: [20717]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:

processor/cumulativetodeltaprocessor/go.mod

@@ -10,7 +10,6 @@ require (
 	go.opentelemetry.io/collector/component v0.75.0
 	go.opentelemetry.io/collector/confmap v0.75.0
 	go.opentelemetry.io/collector/consumer v0.75.0
-	go.opentelemetry.io/collector/featuregate v0.75.0
 	go.opentelemetry.io/collector/pdata v1.0.0-rc9
 	go.uber.org/zap v1.24.0
 )
@@ -31,6 +30,7 @@ require (
 	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	go.opencensus.io v0.24.0 // indirect
+	go.opentelemetry.io/collector/featuregate v0.75.0 // indirect
 	go.opentelemetry.io/otel v1.14.0 // indirect
 	go.opentelemetry.io/otel/metric v0.37.0 // indirect
 	go.opentelemetry.io/otel/trace v1.14.0 // indirect

processor/cumulativetodeltaprocessor/processor.go

@@ -18,38 +18,27 @@ import (
 	"context"
 	"math"
 
-	"go.opentelemetry.io/collector/featuregate"
 	"go.opentelemetry.io/collector/pdata/pmetric"
 	"go.uber.org/zap"
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/internal/filter/filterset"
 	"github.com/open-telemetry/opentelemetry-collector-contrib/processor/cumulativetodeltaprocessor/internal/tracking"
 )
 
-var enableHistogramSupportGate = featuregate.GlobalRegistry().MustRegister(
-	"processor.cumulativetodeltaprocessor.EnableHistogramSupport",
-	featuregate.StageStable,
-	featuregate.WithRegisterDescription("Enables histogram conversion support"),
-	featuregate.WithRegisterReferenceURL("https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/15658"),
-	featuregate.WithRegisterRemovalVersion("v0.68.0"),
-)
-
 type cumulativeToDeltaProcessor struct {
-	includeFS               filterset.FilterSet
-	excludeFS               filterset.FilterSet
-	logger                  *zap.Logger
-	deltaCalculator         *tracking.MetricTracker
-	cancelFunc              context.CancelFunc
-	histogramSupportEnabled bool
+	includeFS       filterset.FilterSet
+	excludeFS       filterset.FilterSet
+	logger          *zap.Logger
+	deltaCalculator *tracking.MetricTracker
+	cancelFunc      context.CancelFunc
 }
 
 func newCumulativeToDeltaProcessor(config *Config, logger *zap.Logger) *cumulativeToDeltaProcessor {
 	ctx, cancel := context.WithCancel(context.Background())
 	p := &cumulativeToDeltaProcessor{
-		logger:                  logger,
-		deltaCalculator:         tracking.NewMetricTracker(ctx, logger, config.MaxStaleness),
-		cancelFunc:              cancel,
-		histogramSupportEnabled: enableHistogramSupportGate.IsEnabled(),
+		logger:          logger,
+		deltaCalculator: tracking.NewMetricTracker(ctx, logger, config.MaxStaleness),
+		cancelFunc:      cancel,
 	}
 	if len(config.Include.Metrics) > 0 {
 		p.includeFS, _ = filterset.CreateFilterSet(config.Include.Metrics, &config.Include.Config)
@@ -92,10 +81,6 @@ func (ctdp *cumulativeToDeltaProcessor) processMetrics(_ context.Context, md pme
 					ms.SetAggregationTemporality(pmetric.AggregationTemporalityDelta)
 					return ms.DataPoints().Len() == 0
 				case pmetric.MetricTypeHistogram:
-					if !ctdp.histogramSupportEnabled {
-						return false
-					}
-
 					ms := m.Histogram()
 					if ms.AggregationTemporality() != pmetric.AggregationTemporalityCumulative {
 						return false