Add a property in ndk_library for header contributions

The new property will be used to determine the header file contributions of
ndk_library(s) to the Public API surface. This should be a no-op for
regular Soong builds.

This will be used by a future bp2build converter to populate
the BUILD files for Multi-tree `cc_api_contribution` targets

(Also noticed that sdk_test.go was never added to testSrcs, which this
CL should fix)

Test: go test ./cc
Test: TH

Change-Id: Ieea093e4aac68e341c6414b6cafe02c441643cdf

cc/Android.bp

@@ -99,10 +99,12 @@ bootstrap_go_package {
         "library_headers_test.go",
         "library_stub_test.go",
         "library_test.go",
+        "ndk_test.go",
         "object_test.go",
         "prebuilt_test.go",
         "proto_test.go",
         "sanitize_test.go",
+        "sdk_test.go",
         "test_data_test.go",
         "tidy_test.go",
         "vendor_public_library_test.go",

cc/cc.go

@@ -2350,7 +2350,10 @@ func (c *Module) DepsMutator(actx android.BottomUpMutatorContext) {
 
 		lib = GetReplaceModuleName(lib, GetSnapshot(c, &snapshotInfo, actx).HeaderLibs)
 
-		if c.IsStubs() {
+		if c.isNDKStubLibrary() {
+			// ndk_headers do not have any variations
+			actx.AddFarVariationDependencies([]blueprint.Variation{}, depTag, lib)
+		} else if c.IsStubs() {
 			actx.AddFarVariationDependencies(append(ctx.Target().Variations(), c.ImageVariation()),
 				depTag, lib)
 		} else {

cc/ndk_library.go

@@ -84,11 +84,13 @@ var (
 //
 // Example:
 //
-//	ndk_library {
-//	    name: "libfoo",
-//	    symbol_file: "libfoo.map.txt",
-//	    first_version: "9",
-//	}
+// ndk_library {
+//
+//	name: "libfoo",
+//	symbol_file: "libfoo.map.txt",
+//	first_version: "9",
+//
+// }
 type libraryProperties struct {
 	// Relative path to the symbol map.
 	// An example file can be seen here: TODO(danalbert): Make an example.
@@ -109,6 +111,9 @@ type libraryProperties struct {
 	// where it is enabled pending a fix for http://b/190554910 (no debug info
 	// for asm implemented symbols).
 	Allow_untyped_symbols *bool
+
+	// Headers presented by this library to the Public API Surface
+	Export_header_libs []string
 }
 
 type stubDecorator struct {
@@ -483,8 +488,11 @@ func (c *stubDecorator) compile(ctx ModuleContext, flags Flags, deps PathDeps) O
 	return objs
 }
 
+// Add a dependency on the header modules of this ndk_library
 func (linker *stubDecorator) linkerDeps(ctx DepsContext, deps Deps) Deps {
-	return Deps{}
+	return Deps{
+		HeaderLibs: linker.properties.Export_header_libs,
+	}
 }
 
 func (linker *stubDecorator) Name(name string) string {

cc/ndk_test.go

@@ -0,0 +1,56 @@
+// Copyright 2022 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 cc
+
+import (
+	"testing"
+
+	"github.com/google/blueprint"
+
+	"android/soong/android"
+)
+
+func TestNdkHeaderDependency(t *testing.T) {
+	isDep := func(ctx *android.TestResult, from, toExpected android.Module) bool {
+		foundDep := false
+		ctx.VisitDirectDeps(from, func(toActual blueprint.Module) {
+			if toExpected.Name() == toActual.Name() {
+				foundDep = true
+			}
+		})
+		return foundDep
+	}
+	bp := `
+	ndk_library {
+		name: "libfoo",
+		first_version: "29",
+		symbol_file: "libfoo.map.txt",
+		export_header_libs: ["libfoo_headers"],
+	}
+	ndk_headers {
+		name: "libfoo_headers",
+		srcs: ["foo.h"],
+		license: "NOTICE",
+	}
+	//This module is needed since Soong creates a dep edge on source
+	cc_library {
+		name: "libfoo",
+	}
+	`
+	ctx := prepareForCcTest.RunTestWithBp(t, bp)
+	libfoo := ctx.ModuleForTests("libfoo.ndk", "android_arm64_armv8-a_sdk_shared")
+	libfoo_headers := ctx.ModuleForTests("libfoo_headers", "")
+	android.AssertBoolEquals(t, "Could not find headers of ndk_library", true, isDep(ctx, libfoo.Module(), libfoo_headers.Module()))
+}

cc/testing.go

@@ -41,6 +41,7 @@ func RegisterRequiredBuildComponentsForTest(ctx android.RegistrationContext) {
 	ctx.RegisterModuleType("ndk_prebuilt_static_stl", NdkPrebuiltStaticStlFactory)
 	ctx.RegisterModuleType("ndk_prebuilt_object", NdkPrebuiltObjectFactory)
 	ctx.RegisterModuleType("ndk_library", NdkLibraryFactory)
+	ctx.RegisterModuleType("ndk_headers", ndkHeadersFactory)
 }
 
 func GatherRequiredDepsForTest(oses ...android.OsType) string {