refactor: Remove unused tempImports concept (#2215)

Author: brianquinlan

internal/sidekick/internal/dart/annotate.go

@@ -281,7 +281,7 @@ func (annotate *annotateModel) annotateModel(options map[string]string) error {
 
 	// Traverse and annotate the messages defined in this API.
 	for _, m := range model.Messages {
-		annotate.annotateMessage(m, annotate.imports)
+		annotate.annotateMessage(m)
 	}
 
 	for _, s := range model.Services {
@@ -436,9 +436,9 @@ func (annotate *annotateModel) annotateService(s *api.Service) {
 	s.Codec = ann
 }
 
-func (annotate *annotateModel) annotateMessage(m *api.Message, imports map[string]bool) {
+func (annotate *annotateModel) annotateMessage(m *api.Message) {
 	// Add the import for the common JSON helpers.
-	imports[commonHelpersImport] = true
+	annotate.imports[commonHelpersImport] = true
 
 	for _, f := range m.Fields {
 		annotate.annotateField(f)
@@ -450,7 +450,7 @@ func (annotate *annotateModel) annotateMessage(m *api.Message, imports map[strin
 		annotate.annotateEnum(e)
 	}
 	for _, m := range m.Messages {
-		annotate.annotateMessage(m, imports)
+		annotate.annotateMessage(m)
 	}
 
 	constructorBody := ";"
@@ -510,12 +510,11 @@ func createToStringLines(message *api.Message) []string {
 
 func (annotate *annotateModel) annotateMethod(method *api.Method) {
 	// Ignore imports added from the input and output messages.
-	tempImports := map[string]bool{}
 	if method.InputType.Codec == nil {
-		annotate.annotateMessage(method.InputType, tempImports)
+		annotate.annotateMessage(method.InputType)
 	}
 	if method.OutputType.Codec == nil {
-		annotate.annotateMessage(method.OutputType, tempImports)
+		annotate.annotateMessage(method.OutputType)
 	}
 
 	pathInfoAnnotation := &pathInfoAnnotation{

internal/sidekick/internal/dart/annotate_test.go

@@ -247,8 +247,7 @@ func TestAnnotateMessageToString(t *testing.T) {
 		{message: sample.Automatic(), expected: 0},
 	} {
 		t.Run(test.message.Name, func(t *testing.T) {
-			imports := map[string]bool{}
-			annotate.annotateMessage(test.message, imports)
+			annotate.annotateMessage(test.message)
 
 			codec := test.message.Codec.(*messageAnnotation)
 			actual := codec.ToStringLines