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

bp2build/android_app_conversion_test.go

@@ -0,0 +1,92 @@
+// Copyright 2021 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package bp2build
+
+import (
+	"android/soong/android"
+	"android/soong/java"
+
+	"testing"
+)
+
+func runAndroidAppTestCase(t *testing.T, tc bp2buildTestCase) {
+	t.Helper()
+	runBp2BuildTestCase(t, registerAndroidAppModuleTypes, tc)
+}
+
+func registerAndroidAppModuleTypes(ctx android.RegistrationContext) {
+}
+
+func TestMinimalAndroidApp(t *testing.T) {
+	runAndroidAppTestCase(t, bp2buildTestCase{
+		description:                        "Android app - simple example",
+		moduleTypeUnderTest:                "android_app",
+		moduleTypeUnderTestFactory:         java.AndroidAppFactory,
+		moduleTypeUnderTestBp2BuildMutator: java.AppBp2Build,
+		filesystem: map[string]string{
+			"app.java":            "",
+			"res/res.png":         "",
+			"AndroidManifest.xml": "",
+		},
+		blueprint: `
+android_app {
+        name: "TestApp",
+        srcs: ["app.java"],
+        sdk_version: "current",
+}
+`,
+		expectedBazelTargets: []string{
+			makeBazelTarget("android_binary", "TestApp", attrNameToString{
+				"srcs":           `["app.java"]`,
+				"manifest":       `"AndroidManifest.xml"`,
+				"resource_files": `["res/res.png"]`,
+			}),
+		}})
+}
+
+func TestAndroidAppAllSupportedFields(t *testing.T) {
+	runAndroidAppTestCase(t, bp2buildTestCase{
+		description:                        "Android app - all supported fields",
+		moduleTypeUnderTest:                "android_app",
+		moduleTypeUnderTestFactory:         java.AndroidAppFactory,
+		moduleTypeUnderTestBp2BuildMutator: java.AppBp2Build,
+		filesystem: map[string]string{
+			"app.java":                     "",
+			"resa/res.png":                 "",
+			"resb/res.png":                 "",
+			"manifest/AndroidManifest.xml": "",
+		},
+		blueprint: `
+android_app {
+        name: "TestApp",
+        srcs: ["app.java"],
+        sdk_version: "current",
+        package_name: "com.google",
+        resource_dirs: ["resa", "resb"],
+        manifest: "manifest/AndroidManifest.xml",
+}
+`,
+		expectedBazelTargets: []string{
+			makeBazelTarget("android_binary", "TestApp", attrNameToString{
+				"srcs":     `["app.java"]`,
+				"manifest": `"manifest/AndroidManifest.xml"`,
+				"resource_files": `[
+        "resa/res.png",
+        "resb/res.png",
+    ]`,
+				"custom_package": `"com.google"`,
+			}),
+		}})
+}