Add stl property to android_app.

The flag is a Soong version of LOCAL_NDK_STL_VARIANT in apps and app
tests. Unlike in the case of cc_library and its siblings, the only
meaningful value for the make var when it's used in apps is
'c++_shared', in which case we add additional dependency to libc++.

Fixes: 130891985
Test: app_test.go + CtsNdkBinderTestCases
Change-Id: I83f45d375742164fff7f160a734b0686e56b5c38

java/app.go

@@ -85,6 +85,9 @@ type appProperties struct {
 	// list of native libraries that will be provided in or alongside the resulting jar
 	Jni_libs []string `android:"arch_variant"`
 
+	// STL library to use for JNI libraries.
+	Stl *string `android:"arch_variant"`
+
 	// Store native libraries uncompressed in the APK and set the android:extractNativeLibs="false" manifest
 	// flag so that they are used from inside the APK at runtime.  Defaults to true for android_test modules unless
 	// sdk_version or min_sdk_version is set to a version that doesn't support it (<23), defaults to false for other
@@ -149,10 +152,15 @@ type Certificate struct {
 func (a *AndroidApp) DepsMutator(ctx android.BottomUpMutatorContext) {
 	a.Module.deps(ctx)
 
+	if String(a.appProperties.Stl) == "c++_shared" && a.sdkVersion() == "" {
+		ctx.PropertyErrorf("stl", "sdk_version must be set in order to use c++_shared")
+	}
+
 	if !Bool(a.properties.No_framework_libs) && !Bool(a.properties.No_standard_libs) {
 		a.aapt.deps(ctx, sdkContext(a))
 	}
 
+	embedJni := a.shouldEmbedJnis(ctx)
 	for _, jniTarget := range ctx.MultiTargets() {
 		variation := []blueprint.Variation{
 			{Mutator: "arch", Variation: jniTarget.String()},
@@ -162,6 +170,11 @@ func (a *AndroidApp) DepsMutator(ctx android.BottomUpMutatorContext) {
 			target: jniTarget,
 		}
 		ctx.AddFarVariationDependencies(variation, tag, a.appProperties.Jni_libs...)
+		if String(a.appProperties.Stl) == "c++_shared" {
+			if embedJni {
+				ctx.AddFarVariationDependencies(variation, tag, "libc++")
+			}
+		}
 	}
 }
 
@@ -217,6 +230,11 @@ func (a *AndroidApp) shouldUncompressDex(ctx android.ModuleContext) bool {
 	return shouldUncompressDex(ctx, &a.dexpreopter)
 }
 
+func (a *AndroidApp) shouldEmbedJnis(ctx android.BaseModuleContext) bool {
+	return ctx.Config().UnbundledBuild() || Bool(a.appProperties.Use_embedded_native_libs) ||
+		a.appProperties.AlwaysPackageNativeLibs
+}
+
 func (a *AndroidApp) aaptBuildActions(ctx android.ModuleContext) {
 	a.aapt.usesNonSdkApis = Bool(a.Module.deviceProperties.Platform_apis)
 
@@ -305,9 +323,7 @@ func (a *AndroidApp) dexBuildActions(ctx android.ModuleContext) android.Path {
 func (a *AndroidApp) jniBuildActions(jniLibs []jniLib, ctx android.ModuleContext) android.WritablePath {
 	var jniJarFile android.WritablePath
 	if len(jniLibs) > 0 {
-		embedJni := ctx.Config().UnbundledBuild() || Bool(a.appProperties.Use_embedded_native_libs) ||
-			a.appProperties.AlwaysPackageNativeLibs
-		if embedJni {
+		if a.shouldEmbedJnis(ctx) {
 			jniJarFile = android.PathForModuleOut(ctx, "jnilibs.zip")
 			TransformJniLibsToJar(ctx, jniJarFile, jniLibs, a.useEmbeddedNativeLibs(ctx))
 		} else {

java/app_test.go

@@ -1178,3 +1178,64 @@ func TestAndroidAppImport_DpiVariants(t *testing.T) {
 		}
 	}
 }
+
+func TestStl(t *testing.T) {
+	ctx := testJava(t, cc.GatherRequiredDepsForTest(android.Android)+`
+		cc_library {
+			name: "libjni",
+		}
+
+		android_test {
+			name: "stl",
+			jni_libs: ["libjni"],
+			compile_multilib: "both",
+			sdk_version: "current",
+			stl: "c++_shared",
+		}
+
+		android_test {
+			name: "system",
+			jni_libs: ["libjni"],
+			compile_multilib: "both",
+			sdk_version: "current",
+		}
+		`)
+
+	testCases := []struct {
+		name string
+		jnis []string
+	}{
+		{"stl",
+			[]string{
+				"libjni.so",
+				"libc++.so",
+			},
+		},
+		{"system",
+			[]string{
+				"libjni.so",
+			},
+		},
+	}
+
+	for _, test := range testCases {
+		t.Run(test.name, func(t *testing.T) {
+			app := ctx.ModuleForTests(test.name, "android_common")
+			jniLibZip := app.Output("jnilibs.zip")
+			var jnis []string
+			args := strings.Fields(jniLibZip.Args["jarArgs"])
+			for i := 0; i < len(args); i++ {
+				if args[i] == "-f" {
+					jnis = append(jnis, args[i+1])
+					i += 1
+				}
+			}
+			jnisJoined := strings.Join(jnis, " ")
+			for _, jni := range test.jnis {
+				if !strings.Contains(jnisJoined, jni) {
+					t.Errorf("missing jni %q in %q", jni, jnis)
+				}
+			}
+		})
+	}
+}