Initial bp2build converter for android_app.

The only supported attributes at this point are:
- srcs
- manifest
- package_name
- resource_dirs
as they most easily map to bazel's android_binary's srcs, manifest, custom_package, and resource_files respectively.
Allow-listing all apps that use these fields, along with sdk_version and dex_preopt. The latter 2 are ignored by the converter,
- sdk_version because we're currently relying on a single pre-built SDK,
- dex_preopt because,
   1. though it is not supported in Bazel builds yet, it doesn't prevent the apps from building, and
   2. the apps being converted only use the dex_preopt attribute to disable dex_preopt, which is what is happening anyway.

Change-Id: I4a4f771eeb8f60a1cd4844b2ac1ce3df7c070e73
Test: ./build/bazel/scripts/run_presubmits.sh
Bug: 198224074
Bug: 203688791

java/app.go

@@ -45,6 +45,7 @@ func RegisterAppBuildComponents(ctx android.RegistrationContext) {
 	ctx.RegisterModuleType("override_android_test", OverrideAndroidTestModuleFactory)
 
 	android.RegisterBp2BuildMutator("android_app_certificate", AndroidAppCertificateBp2Build)
+	android.RegisterBp2BuildMutator("android_app", AppBp2Build)
 }
 
 // AndroidManifest.xml merging
@@ -139,6 +140,7 @@ type overridableAppProperties struct {
 }
 
 type AndroidApp struct {
+	android.BazelModuleBase
 	Library
 	aapt
 	android.OverridableModuleBase
@@ -1438,3 +1440,47 @@ func androidAppCertificateBp2BuildInternal(ctx android.TopDownMutatorContext, mo
 
 	ctx.CreateBazelTargetModule(props, android.CommonAttributes{Name: module.Name()}, attrs)
 }
+
+type bazelAndroidAppAttributes struct {
+	Srcs           bazel.LabelListAttribute
+	Manifest       bazel.Label
+	Custom_package *string
+	Resource_files bazel.LabelListAttribute
+}
+
+// AppBp2Build is used for android_app.
+func AppBp2Build(ctx android.TopDownMutatorContext) {
+	a, ok := ctx.Module().(*AndroidApp)
+	if !ok || !a.ConvertWithBp2build(ctx) {
+		return
+	}
+	if ctx.ModuleType() != "android_app" {
+		return
+	}
+
+	//TODO(b/209577426): Support multiple arch variants
+	srcs := bazel.MakeLabelListAttribute(android.BazelLabelForModuleSrcExcludes(ctx, a.properties.Srcs, a.properties.Exclude_srcs))
+
+	manifest := proptools.StringDefault(a.aaptProperties.Manifest, "AndroidManifest.xml")
+
+	resourceFiles := bazel.LabelList{
+		Includes: []bazel.Label{},
+	}
+	for _, dir := range android.PathsWithOptionalDefaultForModuleSrc(ctx, a.aaptProperties.Resource_dirs, "res") {
+		files := android.RootToModuleRelativePaths(ctx, androidResourceGlob(ctx, dir))
+		resourceFiles.Includes = append(resourceFiles.Includes, files...)
+	}
+
+	attrs := &bazelAndroidAppAttributes{
+		Srcs:     srcs,
+		Manifest: android.BazelLabelForModuleSrcSingle(ctx, manifest),
+		// TODO(b/209576404): handle package name override by product variable PRODUCT_MANIFEST_PACKAGE_NAME_OVERRIDES
+		Custom_package: a.overridableAppProperties.Package_name,
+		Resource_files: bazel.MakeLabelListAttribute(resourceFiles),
+	}
+	props := bazel.BazelTargetModuleProperties{Rule_class: "android_binary",
+		Bzl_load_location: "@rules_android//rules:rules.bzl"}
+
+	ctx.CreateBazelTargetModule(props, android.CommonAttributes{Name: a.Name()}, attrs)
+
+}