diff --git a/java/app.go b/java/app.go
index 9360cc5..3e24ebc 100644
--- a/java/app.go
+++ b/java/app.go
@@ -17,7 +17,6 @@
 // This file contains the module types for compiling Android apps.
 
 import (
-	"path/filepath"
 	"strings"
 
 	"github.com/google/blueprint/proptools"
@@ -26,11 +25,9 @@
 )
 
 func init() {
-	android.RegisterPreSingletonType("overlay", OverlaySingletonFactory)
 	android.RegisterModuleType("android_app", AndroidAppFactory)
 }
 
-// AAR prebuilts
 // AndroidManifest.xml merging
 // package splits
 
@@ -46,91 +43,59 @@
 	// use to get PRODUCT-agnostic resource data like IDs and type definitions.
 	Export_package_resources *bool
 
-	// flags passed to aapt when creating the apk
-	Aaptflags []string
-
-	// list of resource labels to generate individual resource packages
-	Package_splits []string
-
-	// list of directories relative to the Blueprints file containing assets.
-	// Defaults to "assets"
-	Asset_dirs []string
-
-	// list of directories relative to the Blueprints file containing
-	// Android resources
-	Resource_dirs []string
-
-	Instrumentation_for *string
-
 	// Specifies that this app should be installed to the priv-app directory,
 	// where the system will grant it additional privileges not available to
 	// normal apps.
 	Privileged *bool
+
+	// list of resource labels to generate individual resource packages
+	Package_splits []string
+
+	Instrumentation_for *string
 }
 
 type AndroidApp struct {
-	Module
+	Library
+	aapt
+
+	certificate certificate
 
 	appProperties appProperties
-
-	aaptSrcJar    android.Path
-	exportPackage android.Path
-	rroDirs       android.Paths
-	manifestPath  android.Path
-	certificate   certificate
 }
 
+var _ AndroidLibraryDependency = (*AndroidApp)(nil)
+
 type certificate struct {
 	pem, key android.Path
 }
 
 func (a *AndroidApp) DepsMutator(ctx android.BottomUpMutatorContext) {
 	a.Module.deps(ctx)
-
 	if !Bool(a.properties.No_framework_libs) && !Bool(a.properties.No_standard_libs) {
-		switch String(a.deviceProperties.Sdk_version) { // TODO: Res_sdk_version?
-		case "current", "system_current", "test_current", "":
-			ctx.AddDependency(ctx.Module(), frameworkResTag, "framework-res")
-		default:
-			// We'll already have a dependency on an sdk prebuilt android.jar
-		}
+		a.aapt.deps(ctx, String(a.deviceProperties.Sdk_version))
 	}
 }
 
 func (a *AndroidApp) GenerateAndroidBuildActions(ctx android.ModuleContext) {
-	linkFlags, linkDeps, resDirs, overlayDirs, rroDirs, manifestPath := a.aapt2Flags(ctx)
-
-	packageRes := android.PathForModuleOut(ctx, "package-res.apk")
-	srcJar := android.PathForModuleGen(ctx, "R.jar")
-	proguardOptionsFile := android.PathForModuleGen(ctx, "proguard.options")
-
-	var compiledRes, compiledOverlay android.Paths
-	for _, dir := range resDirs {
-		compiledRes = append(compiledRes, aapt2Compile(ctx, dir.dir, dir.files).Paths()...)
-	}
-	for _, dir := range overlayDirs {
-		compiledOverlay = append(compiledOverlay, aapt2Compile(ctx, dir.dir, dir.files).Paths()...)
+	var linkFlags []string
+	if String(a.appProperties.Instrumentation_for) != "" {
+		linkFlags = append(linkFlags,
+			"--rename-instrumentation-target-package",
+			String(a.appProperties.Instrumentation_for))
+	} else {
+		a.properties.Instrument = true
 	}
 
-	aapt2Link(ctx, packageRes, srcJar, proguardOptionsFile,
-		linkFlags, linkDeps, compiledRes, compiledOverlay)
+	// TODO: LOCAL_PACKAGE_OVERRIDES
+	//    $(addprefix --rename-manifest-package , $(PRIVATE_MANIFEST_PACKAGE_NAME)) \
 
-	a.exportPackage = packageRes
-	a.aaptSrcJar = srcJar
-
-	ctx.CheckbuildFile(proguardOptionsFile)
-	ctx.CheckbuildFile(a.exportPackage)
-	ctx.CheckbuildFile(a.aaptSrcJar)
+	a.aapt.buildActions(ctx, String(a.deviceProperties.Sdk_version), linkFlags...)
 
 	// apps manifests are handled by aapt, don't let Module see them
 	a.properties.Manifest = nil
 
-	if String(a.appProperties.Instrumentation_for) == "" {
-		a.properties.Instrument = true
-	}
-
 	a.Module.extraProguardFlagFiles = append(a.Module.extraProguardFlagFiles,
-		proguardOptionsFile)
+		a.proguardOptionsFile)
 
 	if ctx.ModuleName() != "framework-res" {
 		a.Module.compile(ctx, a.aaptSrcJar)
@@ -167,8 +132,6 @@
 	CreateAppPackage(ctx, packageFile, a.exportPackage, a.outputFile, certificates)
 
 	a.outputFile = packageFile
-	a.rroDirs = rroDirs
-	a.manifestPath = manifestPath
 
 	if ctx.ModuleName() == "framework-res" {
 		// framework-res.apk is installed as system/framework/framework-res.apk
@@ -180,161 +143,6 @@
 	}
 }
 
-var aaptIgnoreFilenames = []string{
-	".svn",
-	".git",
-	".ds_store",
-	"*.scc",
-	".*",
-	"CVS",
-	"thumbs.db",
-	"picasa.ini",
-	"*~",
-}
-
-type globbedResourceDir struct {
-	dir   android.Path
-	files android.Paths
-}
-
-func (a *AndroidApp) aapt2Flags(ctx android.ModuleContext) (flags []string, deps android.Paths,
-	resDirs, overlayDirs []globbedResourceDir, rroDirs android.Paths, manifestPath android.Path) {
-
-	hasVersionCode := false
-	hasVersionName := false
-	hasProduct := false
-	for _, f := range a.appProperties.Aaptflags {
-		if strings.HasPrefix(f, "--version-code") {
-			hasVersionCode = true
-		} else if strings.HasPrefix(f, "--version-name") {
-			hasVersionName = true
-		} else if strings.HasPrefix(f, "--product") {
-			hasProduct = true
-		}
-	}
-
-	var linkFlags []string
-
-	// Flags specified in Android.bp
-	linkFlags = append(linkFlags, a.appProperties.Aaptflags...)
-
-	linkFlags = append(linkFlags, "--no-static-lib-packages")
-
-	// Find implicit or explicit asset and resource dirs
-	assetDirs := android.PathsWithOptionalDefaultForModuleSrc(ctx, a.appProperties.Asset_dirs, "assets")
-	resourceDirs := android.PathsWithOptionalDefaultForModuleSrc(ctx, a.appProperties.Resource_dirs, "res")
-
-	var linkDeps android.Paths
-
-	// Glob directories into lists of paths
-	for _, dir := range resourceDirs {
-		resDirs = append(resDirs, globbedResourceDir{
-			dir:   dir,
-			files: resourceGlob(ctx, dir),
-		})
-		resOverlayDirs, resRRODirs := overlayResourceGlob(ctx, dir)
-		overlayDirs = append(overlayDirs, resOverlayDirs...)
-		rroDirs = append(rroDirs, resRRODirs...)
-	}
-
-	var assetFiles android.Paths
-	for _, dir := range assetDirs {
-		assetFiles = append(assetFiles, resourceGlob(ctx, dir)...)
-	}
-
-	// App manifest file
-	var manifestFile string
-	if a.properties.Manifest == nil {
-		manifestFile = "AndroidManifest.xml"
-	} else {
-		manifestFile = *a.properties.Manifest
-	}
-
-	manifestPath = android.PathForModuleSrc(ctx, manifestFile)
-	linkFlags = append(linkFlags, "--manifest "+manifestPath.String())
-	linkDeps = append(linkDeps, manifestPath)
-
-	linkFlags = append(linkFlags, android.JoinWithPrefix(assetDirs.Strings(), "-A "))
-	linkDeps = append(linkDeps, assetFiles...)
-
-	// Include dirs
-	ctx.VisitDirectDeps(func(module android.Module) {
-		var depFiles android.Paths
-		if javaDep, ok := module.(Dependency); ok {
-			// TODO: shared android libraries
-			if ctx.OtherModuleName(module) == "framework-res" {
-				depFiles = android.Paths{javaDep.(*AndroidApp).exportPackage}
-			}
-		}
-
-		for _, dep := range depFiles {
-			linkFlags = append(linkFlags, "-I "+dep.String())
-		}
-		linkDeps = append(linkDeps, depFiles...)
-	})
-
-	sdkDep := decodeSdkDep(ctx, String(a.deviceProperties.Sdk_version))
-	if sdkDep.useFiles {
-		linkFlags = append(linkFlags, "-I "+sdkDep.jar.String())
-		linkDeps = append(linkDeps, sdkDep.jar)
-	}
-
-	// SDK version flags
-	sdkVersion := String(a.deviceProperties.Sdk_version)
-	switch sdkVersion {
-	case "", "current", "system_current", "test_current":
-		sdkVersion = proptools.NinjaEscape([]string{ctx.Config().DefaultAppTargetSdk()})[0]
-	}
-
-	linkFlags = append(linkFlags, "--min-sdk-version "+sdkVersion)
-	linkFlags = append(linkFlags, "--target-sdk-version "+sdkVersion)
-
-	// Product characteristics
-	if !hasProduct && len(ctx.Config().ProductAAPTCharacteristics()) > 0 {
-		linkFlags = append(linkFlags, "--product", ctx.Config().ProductAAPTCharacteristics())
-	}
-
-	// Product AAPT config
-	for _, aaptConfig := range ctx.Config().ProductAAPTConfig() {
-		linkFlags = append(linkFlags, "-c", aaptConfig)
-	}
-
-	// Product AAPT preferred config
-	if len(ctx.Config().ProductAAPTPreferredConfig()) > 0 {
-		linkFlags = append(linkFlags, "--preferred-density", ctx.Config().ProductAAPTPreferredConfig())
-	}
-
-	// Version code
-	if !hasVersionCode {
-		linkFlags = append(linkFlags, "--version-code", ctx.Config().PlatformSdkVersion())
-	}
-
-	if !hasVersionName {
-		var versionName string
-		if ctx.ModuleName() == "framework-res" {
-			// Some builds set AppsDefaultVersionName() to include the build number ("O-123456").  aapt2 copies the
-			// version name of framework-res into app manifests as compileSdkVersionCodename, which confuses things
-			// if it contains the build number.  Use the DefaultAppTargetSdk instead.
-			versionName = ctx.Config().DefaultAppTargetSdk()
-		} else {
-			versionName = ctx.Config().AppsDefaultVersionName()
-		}
-		versionName = proptools.NinjaEscape([]string{versionName})[0]
-		linkFlags = append(linkFlags, "--version-name ", versionName)
-	}
-
-	if String(a.appProperties.Instrumentation_for) != "" {
-		linkFlags = append(linkFlags,
-			"--rename-instrumentation-target-package",
-			String(a.appProperties.Instrumentation_for))
-	}
-
-	// TODO: LOCAL_PACKAGE_OVERRIDES
-	//    $(addprefix --rename-manifest-package , $(PRIVATE_MANIFEST_PACKAGE_NAME)) \
-
-	return linkFlags, linkDeps, resDirs, overlayDirs, rroDirs, manifestPath
-}
-
 func AndroidAppFactory() android.Module {
 	module := &AndroidApp{}
 
@@ -344,92 +152,10 @@
 	module.AddProperties(
 		&module.Module.properties,
 		&module.Module.deviceProperties,
+		&module.Module.protoProperties,
+		&module.aaptProperties,
 		&module.appProperties)
 
 	android.InitAndroidArchModule(module, android.DeviceSupported, android.MultilibCommon)
 	return module
 }
-
-func resourceGlob(ctx android.ModuleContext, dir android.Path) android.Paths {
-	return ctx.GlobFiles(filepath.Join(dir.String(), "**/*"), aaptIgnoreFilenames)
-}
-
-type overlayGlobResult struct {
-	dir   string
-	paths android.DirectorySortedPaths
-
-	// Set to true of the product has selected that values in this overlay should not be moved to
-	// Runtime Resource Overlay (RRO) packages.
-	excludeFromRRO bool
-}
-
-const overlayDataKey = "overlayDataKey"
-
-func overlayResourceGlob(ctx android.ModuleContext, dir android.Path) (res []globbedResourceDir,
-	rroDirs android.Paths) {
-
-	overlayData := ctx.Config().Get(overlayDataKey).([]overlayGlobResult)
-
-	// Runtime resource overlays (RRO) may be turned on by the product config for some modules
-	rroEnabled := ctx.Config().EnforceRROForModule(ctx.ModuleName())
-
-	for _, data := range overlayData {
-		files := data.paths.PathsInDirectory(filepath.Join(data.dir, dir.String()))
-		if len(files) > 0 {
-			overlayModuleDir := android.PathForSource(ctx, data.dir, dir.String())
-			// If enforce RRO is enabled for this module and this overlay is not in the
-			// exclusion list, ignore the overlay.  The list of ignored overlays will be
-			// passed to Make to be turned into an RRO package.
-			if rroEnabled && !data.excludeFromRRO {
-				rroDirs = append(rroDirs, overlayModuleDir)
-			} else {
-				res = append(res, globbedResourceDir{
-					dir:   overlayModuleDir,
-					files: files,
-				})
-			}
-		}
-	}
-
-	return res, rroDirs
-}
-
-func OverlaySingletonFactory() android.Singleton {
-	return overlaySingleton{}
-}
-
-type overlaySingleton struct{}
-
-func (overlaySingleton) GenerateBuildActions(ctx android.SingletonContext) {
-	var overlayData []overlayGlobResult
-	overlayDirs := ctx.Config().ResourceOverlays()
-	for i := range overlayDirs {
-		// Iterate backwards through the list of overlay directories so that the later, lower-priority
-		// directories in the list show up earlier in the command line to aapt2.
-		overlay := overlayDirs[len(overlayDirs)-1-i]
-		var result overlayGlobResult
-		result.dir = overlay
-
-		// Mark overlays that will not have Runtime Resource Overlays enforced on them
-		// based on the product config
-		result.excludeFromRRO = ctx.Config().EnforceRROExcludedOverlay(overlay)
-
-		files, err := ctx.GlobWithDeps(filepath.Join(overlay, "**/*"), aaptIgnoreFilenames)
-		if err != nil {
-			ctx.Errorf("failed to glob resource dir %q: %s", overlay, err.Error())
-			continue
-		}
-		var paths android.Paths
-		for _, f := range files {
-			if !strings.HasSuffix(f, "/") {
-				paths = append(paths, android.PathForSource(ctx, f))
-			}
-		}
-		result.paths = android.PathsToDirectorySortedPaths(paths)
-		overlayData = append(overlayData, result)
-	}
-
-	ctx.Config().Once(overlayDataKey, func() interface{} {
-		return overlayData
-	})
-}