Add defaults support for apex_contributions module type

Bug: 326246905
Test: go build ./android

Change-Id: I8be21594465d81c99c216b0fcbf9996aed46c209
diff --git a/android/apex_contributions.go b/android/apex_contributions.go
index 89e27b9..c1216c6 100644
--- a/android/apex_contributions.go
+++ b/android/apex_contributions.go
@@ -25,11 +25,13 @@
 
 func RegisterApexContributionsBuildComponents(ctx RegistrationContext) {
 	ctx.RegisterModuleType("apex_contributions", apexContributionsFactory)
+	ctx.RegisterModuleType("apex_contributions_defaults", apexContributionsDefaultsFactory)
 	ctx.RegisterSingletonModuleType("all_apex_contributions", allApexContributionsFactory)
 }
 
 type apexContributions struct {
 	ModuleBase
+	DefaultableModuleBase
 	properties contributionProps
 }
 
@@ -59,6 +61,7 @@
 	module := &apexContributions{}
 	module.AddProperties(&module.properties)
 	InitAndroidModule(module)
+	InitDefaultableModule(module)
 	return module
 }
 
@@ -68,6 +71,18 @@
 func (m *apexContributions) GenerateAndroidBuildActions(ctx ModuleContext) {
 }
 
+type apexContributionsDefaults struct {
+	ModuleBase
+	DefaultsModuleBase
+}
+
+func apexContributionsDefaultsFactory() Module {
+	module := &apexContributionsDefaults{}
+	module.AddProperties(&contributionProps{})
+	InitDefaultsModule(module)
+	return module
+}
+
 // A container for apex_contributions.
 // Based on product_config, it will create a dependency on the selected
 // apex_contributions per mainline module