diff --git a/android/defaults.go b/android/defaults.go
index a821b28..31d6014 100644
--- a/android/defaults.go
+++ b/android/defaults.go
@@ -15,8 +15,6 @@
 package android
 
 import (
-	"bytes"
-	"fmt"
 	"reflect"
 
 	"github.com/google/blueprint"
@@ -69,11 +67,9 @@
 	// Set the property structures into which defaults will be added.
 	setProperties(props []interface{}, variableProperties interface{})
 
-	// Apply defaults from the supplied DefaultsModule to the property structures supplied to
+	// Apply defaults from the supplied Defaults to the property structures supplied to
 	// setProperties(...).
-	applyDefaults(TopDownMutatorContext, []DefaultsModule)
-
-	applySingleDefaultsWithTracker(EarlyModuleContext, DefaultsModule, defaultsTrackerFunc)
+	applyDefaults(TopDownMutatorContext, []Defaults)
 
 	// Set the hook to be called after any defaults have been applied.
 	//
@@ -119,23 +115,9 @@
 	Defaults_visibility []string
 }
 
-// AdditionalDefaultsProperties contains properties of defaults modules which
-// can have other defaults applied.
-type AdditionalDefaultsProperties struct {
-
-	// The list of properties set by the default whose values must not be changed by any module that
-	// applies these defaults. It is an error if a property is not supported by the defaults module or
-	// has not been set to a non-zero value. If this contains "*" then that must be the only entry in
-	// which case all properties that are set on this defaults will be protected (except the
-	// protected_properties and visibility.
-	Protected_properties []string
-}
-
 type DefaultsModuleBase struct {
 	DefaultableModuleBase
 
-	defaultsProperties AdditionalDefaultsProperties
-
 	// Included to support setting bazel_module.label for multiple Soong modules to the same Bazel
 	// target. This is primarily useful for modules that were architecture specific and instead are
 	// handled in Bazel as a select().
@@ -169,18 +151,6 @@
 	// DefaultsModuleBase will type-assert to the Defaults interface.
 	isDefaults() bool
 
-	// additionalDefaultableProperties returns additional properties provided by the defaults which
-	// can themselves have defaults applied.
-	additionalDefaultableProperties() []interface{}
-
-	// protectedProperties returns the names of the properties whose values cannot be changed by a
-	// module that applies these defaults.
-	protectedProperties() []string
-
-	// setProtectedProperties sets the names of the properties whose values cannot be changed by a
-	// module that applies these defaults.
-	setProtectedProperties(protectedProperties []string)
-
 	// Get the structures containing the properties for which defaults can be provided.
 	properties() []interface{}
 
@@ -197,18 +167,6 @@
 	Bazelable
 }
 
-func (d *DefaultsModuleBase) additionalDefaultableProperties() []interface{} {
-	return []interface{}{&d.defaultsProperties}
-}
-
-func (d *DefaultsModuleBase) protectedProperties() []string {
-	return d.defaultsProperties.Protected_properties
-}
-
-func (d *DefaultsModuleBase) setProtectedProperties(protectedProperties []string) {
-	d.defaultsProperties.Protected_properties = protectedProperties
-}
-
 func (d *DefaultsModuleBase) properties() []interface{} {
 	return d.defaultableProperties
 }
@@ -232,10 +190,6 @@
 		&ApexProperties{},
 		&distProperties{})
 
-	// Additional properties of defaults modules that can themselves have
-	// defaults applied.
-	module.AddProperties(module.additionalDefaultableProperties()...)
-
 	// Bazel module must be initialized _before_ Defaults to be included in cc_defaults module.
 	InitBazelModule(module)
 	initAndroidModuleBase(module)
@@ -263,58 +217,6 @@
 
 	// The applicable licenses property for defaults is 'licenses'.
 	setPrimaryLicensesProperty(module, "licenses", &commonProperties.Licenses)
-
-	AddLoadHook(module, func(ctx LoadHookContext) {
-
-		protectedProperties := module.protectedProperties()
-		if len(protectedProperties) == 0 {
-			return
-		}
-
-		propertiesAvailable := map[string]struct{}{}
-		propertiesSet := map[string]struct{}{}
-
-		// A defaults tracker which will keep track of which properties have been set on this module.
-		collector := func(defaults DefaultsModule, property string, dstValue interface{}, srcValue interface{}) bool {
-			value := reflect.ValueOf(dstValue)
-			propertiesAvailable[property] = struct{}{}
-			if !value.IsZero() {
-				propertiesSet[property] = struct{}{}
-			}
-			// Skip all the properties so that there are no changes to the defaults.
-			return false
-		}
-
-		// Try and apply this module's defaults to itself, so that the properties can be collected but
-		// skip all the properties so it doesn't actually do anything.
-		module.applySingleDefaultsWithTracker(ctx, module, collector)
-
-		if InList("*", protectedProperties) {
-			if len(protectedProperties) != 1 {
-				ctx.PropertyErrorf("protected_properties", `if specified then "*" must be the only property listed`)
-				return
-			}
-
-			// Do not automatically protect the protected_properties property.
-			delete(propertiesSet, "protected_properties")
-
-			// Or the visibility property.
-			delete(propertiesSet, "visibility")
-
-			// Replace the "*" with the names of all the properties that have been set.
-			protectedProperties = SortedKeys(propertiesSet)
-			module.setProtectedProperties(protectedProperties)
-		} else {
-			for _, property := range protectedProperties {
-				if _, ok := propertiesAvailable[property]; !ok {
-					ctx.PropertyErrorf(property, "property is not supported by this module type %q",
-						ctx.ModuleType())
-				} else if _, ok := propertiesSet[property]; !ok {
-					ctx.PropertyErrorf(property, "is not set; protected properties must be explicitly set")
-				}
-			}
-		}
-	})
 }
 
 var _ Defaults = (*DefaultsModuleBase)(nil)
@@ -366,204 +268,35 @@
 	b.setNamespacedVariableProps(dst)
 }
 
-// defaultValueInfo contains information about each default value that applies to a protected
-// property.
-type defaultValueInfo struct {
-	// The DefaultsModule providing the value, which may be defined on that module or applied as a
-	// default from other modules.
-	module Module
-
-	// The default value, as returned by getComparableValue
-	defaultValue reflect.Value
-}
-
-// protectedPropertyInfo contains information about each property that has to be protected when
-// applying defaults.
-type protectedPropertyInfo struct {
-	// True if the property was set on the module to which defaults are applied, this is an error.
-	propertySet bool
-
-	// The original value of the property on the module, as returned by getComparableValue.
-	originalValue reflect.Value
-
-	// A list of defaults for the property that are being applied.
-	defaultValues []defaultValueInfo
-}
-
-// getComparableValue takes a reflect.Value that may be a pointer to another value and returns a
-// reflect.Value to the underlying data or the original if was not a pointer or was nil. The
-// returned values can then be compared for equality.
-func getComparableValue(value reflect.Value) reflect.Value {
-	if value.IsZero() {
-		return value
-	}
-	for value.Kind() == reflect.Ptr {
-		value = value.Elem()
-	}
-	return value
-}
-
 func (defaultable *DefaultableModuleBase) applyDefaults(ctx TopDownMutatorContext,
-	defaultsList []DefaultsModule) {
-
-	// Collate information on all the properties protected by each of the default modules applied
-	// to this module.
-	allProtectedProperties := map[string]*protectedPropertyInfo{}
-	for _, defaults := range defaultsList {
-		for _, property := range defaults.protectedProperties() {
-			info := allProtectedProperties[property]
-			if info == nil {
-				info = &protectedPropertyInfo{}
-				allProtectedProperties[property] = info
-			}
-		}
-	}
-
-	// If there are any protected properties then collate information about attempts to change them.
-	var protectedPropertyInfoCollector defaultsTrackerFunc
-	if len(allProtectedProperties) > 0 {
-		protectedPropertyInfoCollector = func(defaults DefaultsModule, property string,
-			dstValue interface{}, srcValue interface{}) bool {
-
-			// If the property is not protected then return immediately.
-			info := allProtectedProperties[property]
-			if info == nil {
-				return true
-			}
-
-			currentValue := reflect.ValueOf(dstValue)
-			if info.defaultValues == nil {
-				info.propertySet = !currentValue.IsZero()
-				info.originalValue = getComparableValue(currentValue)
-			}
-
-			defaultValue := reflect.ValueOf(srcValue)
-			if !defaultValue.IsZero() {
-				info.defaultValues = append(info.defaultValues,
-					defaultValueInfo{defaults, getComparableValue(defaultValue)})
-			}
-
-			return true
-		}
-	}
+	defaultsList []Defaults) {
 
 	for _, defaults := range defaultsList {
 		if ctx.Config().BuildMode == Bp2build {
 			applyNamespacedVariableDefaults(defaults, ctx)
 		}
-
-		defaultable.applySingleDefaultsWithTracker(ctx, defaults, protectedPropertyInfoCollector)
-	}
-
-	// Check the status of any protected properties.
-	for property, info := range allProtectedProperties {
-		if len(info.defaultValues) == 0 {
-			// No defaults were applied to the protected properties. Possibly because this module type
-			// does not support any of them.
-			continue
-		}
-
-		// Check to make sure that there are no conflicts between the defaults.
-		conflictingDefaults := false
-		previousDefaultValue := reflect.ValueOf(false)
-		for _, defaultInfo := range info.defaultValues {
-			defaultValue := defaultInfo.defaultValue
-			if previousDefaultValue.IsZero() {
-				previousDefaultValue = defaultValue
-			} else if !reflect.DeepEqual(previousDefaultValue.Interface(), defaultValue.Interface()) {
-				conflictingDefaults = true
-				break
-			}
-		}
-
-		if conflictingDefaults {
-			var buf bytes.Buffer
-			for _, defaultInfo := range info.defaultValues {
-				buf.WriteString(fmt.Sprintf("\n    defaults module %q provides value %#v",
-					ctx.OtherModuleName(defaultInfo.module), defaultInfo.defaultValue))
-			}
-			result := buf.String()
-			ctx.ModuleErrorf("has conflicting default values for protected property %q:%s", property, result)
-			continue
-		}
-
-		// Now check to see whether there the current module tried to override/append to the defaults.
-		if info.propertySet {
-			originalValue := info.originalValue
-			// Just compare against the first defaults.
-			defaultValue := info.defaultValues[0].defaultValue
-			defaults := info.defaultValues[0].module
-
-			if originalValue.Kind() == reflect.Slice {
-				ctx.ModuleErrorf("attempts to append %q to protected property %q's value of %q defined in module %q",
-					originalValue,
-					property,
-					defaultValue,
-					ctx.OtherModuleName(defaults))
+		for _, prop := range defaultable.defaultableProperties {
+			if prop == defaultable.defaultableVariableProperties {
+				defaultable.applyDefaultVariableProperties(ctx, defaults, prop)
 			} else {
-				same := reflect.DeepEqual(originalValue.Interface(), defaultValue.Interface())
-				message := ""
-				if same {
-					message = fmt.Sprintf(" with a matching value (%#v) so this property can simply be removed.", originalValue)
-				} else {
-					message = fmt.Sprintf(" with a different value (override %#v with %#v) so removing the property may necessitate other changes.", defaultValue, originalValue)
-				}
-				ctx.ModuleErrorf("attempts to override protected property %q defined in module %q%s",
-					property,
-					ctx.OtherModuleName(defaults), message)
+				defaultable.applyDefaultProperties(ctx, defaults, prop)
 			}
 		}
 	}
 }
 
-func (defaultable *DefaultableModuleBase) applySingleDefaultsWithTracker(ctx EarlyModuleContext, defaults DefaultsModule, tracker defaultsTrackerFunc) {
-	for _, prop := range defaultable.defaultableProperties {
-		var err error
-		if prop == defaultable.defaultableVariableProperties {
-			err = defaultable.applyDefaultVariableProperties(defaults, prop, tracker)
-		} else {
-			err = defaultable.applyDefaultProperties(defaults, prop, tracker)
-		}
-		if err != nil {
-			if propertyErr, ok := err.(*proptools.ExtendPropertyError); ok {
-				ctx.PropertyErrorf(propertyErr.Property, "%s", propertyErr.Err.Error())
-			} else {
-				panic(err)
-			}
-		}
-	}
-}
-
-// defaultsTrackerFunc is the type of a function that can be used to track how defaults are applied.
-type defaultsTrackerFunc func(defaults DefaultsModule, property string,
-	dstValue interface{}, srcValue interface{}) bool
-
-// filterForTracker wraps a defaultsTrackerFunc in a proptools.ExtendPropertyFilterFunc
-func filterForTracker(defaults DefaultsModule, tracker defaultsTrackerFunc) proptools.ExtendPropertyFilterFunc {
-	if tracker == nil {
-		return nil
-	}
-	return func(property string,
-		dstField, srcField reflect.StructField,
-		dstValue, srcValue interface{}) (bool, error) {
-
-		apply := tracker(defaults, property, dstValue, srcValue)
-		return apply, nil
-	}
-}
-
 // Product variable properties need special handling, the type of the filtered product variable
 // property struct may not be identical between the defaults module and the defaultable module.
 // Use PrependMatchingProperties to apply whichever properties match.
-func (defaultable *DefaultableModuleBase) applyDefaultVariableProperties(defaults DefaultsModule,
-	defaultableProp interface{}, tracker defaultsTrackerFunc) error {
+func (defaultable *DefaultableModuleBase) applyDefaultVariableProperties(ctx TopDownMutatorContext,
+	defaults Defaults, defaultableProp interface{}) {
 	if defaultableProp == nil {
-		return nil
+		return
 	}
 
 	defaultsProp := defaults.productVariableProperties()
 	if defaultsProp == nil {
-		return nil
+		return
 	}
 
 	dst := []interface{}{
@@ -573,26 +306,31 @@
 		proptools.CloneEmptyProperties(reflect.ValueOf(defaultsProp)).Interface(),
 	}
 
-	filter := filterForTracker(defaults, tracker)
-
-	return proptools.PrependMatchingProperties(dst, defaultsProp, filter)
+	err := proptools.PrependMatchingProperties(dst, defaultsProp, nil)
+	if err != nil {
+		if propertyErr, ok := err.(*proptools.ExtendPropertyError); ok {
+			ctx.PropertyErrorf(propertyErr.Property, "%s", propertyErr.Err.Error())
+		} else {
+			panic(err)
+		}
+	}
 }
 
-func (defaultable *DefaultableModuleBase) applyDefaultProperties(defaults DefaultsModule,
-	defaultableProp interface{}, checker defaultsTrackerFunc) error {
-
-	filter := filterForTracker(defaults, checker)
+func (defaultable *DefaultableModuleBase) applyDefaultProperties(ctx TopDownMutatorContext,
+	defaults Defaults, defaultableProp interface{}) {
 
 	for _, def := range defaults.properties() {
 		if proptools.TypeEqual(defaultableProp, def) {
-			err := proptools.PrependProperties(defaultableProp, def, filter)
+			err := proptools.PrependProperties(defaultableProp, def, nil)
 			if err != nil {
-				return err
+				if propertyErr, ok := err.(*proptools.ExtendPropertyError); ok {
+					ctx.PropertyErrorf(propertyErr.Property, "%s", propertyErr.Err.Error())
+				} else {
+					panic(err)
+				}
 			}
 		}
 	}
-
-	return nil
 }
 
 func RegisterDefaultsPreArchMutators(ctx RegisterMutatorsContext) {
@@ -609,12 +347,12 @@
 func defaultsMutator(ctx TopDownMutatorContext) {
 	if defaultable, ok := ctx.Module().(Defaultable); ok {
 		if len(defaultable.defaults().Defaults) > 0 {
-			var defaultsList []DefaultsModule
+			var defaultsList []Defaults
 			seen := make(map[Defaults]bool)
 
 			ctx.WalkDeps(func(module, parent Module) bool {
 				if ctx.OtherModuleDependencyTag(module) == DefaultsDepTag {
-					if defaults, ok := module.(DefaultsModule); ok {
+					if defaults, ok := module.(Defaults); ok {
 						if !seen[defaults] {
 							seen[defaults] = true
 							defaultsList = append(defaultsList, defaults)