Refactor Task Results Substitution

While working on When Expressions, found that this refactor would make
it easier to extend Task Results Substitution to When Expressions.
Specifically moving the logic to get the results refs to resultrefresolution.go
and splitting the logic to two functions with separate concerns.

pkg/reconciler/pipelinerun/resources/apply.go

@@ -67,13 +67,7 @@ func ApplyContexts(spec *v1beta1.PipelineSpec, pipelineName string, pr *v1beta1.
 
 // ApplyTaskResults applies the ResolvedResultRef to each PipelineTask.Params in targets
 func ApplyTaskResults(targets PipelineRunState, resolvedResultRefs ResolvedResultRefs) {
-	stringReplacements := map[string]string{}
-
-	for _, resolvedResultRef := range resolvedResultRefs {
-		replaceTarget := fmt.Sprintf("%s.%s.%s.%s", v1beta1.ResultTaskPart, resolvedResultRef.ResultReference.PipelineTask, v1beta1.ResultResultPart, resolvedResultRef.ResultReference.Result)
-		stringReplacements[replaceTarget] = resolvedResultRef.Value.StringVal
-	}
-
+	stringReplacements := resolvedResultRefs.getStringReplacements()
 	for _, resolvedPipelineRunTask := range targets {
 		// also make substitution for resolved condition checks
 		for _, resolvedConditionCheck := range resolvedPipelineRunTask.ResolvedConditionChecks {

pkg/reconciler/pipelinerun/resources/resultrefresolution.go

@@ -266,3 +266,16 @@ func findTaskResultForParam(taskRun *v1beta1.TaskRun, reference *v1beta1.ResultR
 	}
 	return nil, fmt.Errorf("Could not find result with name %s for task run %s", reference.Result, reference.PipelineTask)
 }
+
+func (rs ResolvedResultRefs) getStringReplacements() map[string]string {
+	replacements := map[string]string{}
+	for _, r := range rs {
+		replaceTarget := r.getReplaceTarget()
+		replacements[replaceTarget] = r.Value.StringVal
+	}
+	return replacements
+}
+
+func (r *ResolvedResultRef) getReplaceTarget() string {
+	return fmt.Sprintf("%s.%s.%s.%s", v1beta1.ResultTaskPart, r.ResultReference.PipelineTask, v1beta1.ResultResultPart, r.ResultReference.Result)
+}