Incorporate cc_library_headers into mixed builds

Test: go soong tests
Test: bp2build generate & sync; mixed build libc; mixed build su (su is
      an Android.mk target that relies on converted a cc_library_headers)
Bug: 181552740
Change-Id: I9efd587970551fd41f642a208f0aa0a80e8694e0

cc/library_headers.go

@@ -43,6 +43,52 @@ func RegisterLibraryHeadersBuildComponents(ctx android.RegistrationContext) {
 	ctx.RegisterModuleType("cc_prebuilt_library_headers", prebuiltLibraryHeaderFactory)
 }
 
+type libraryHeaderBazelHander struct {
+	bazelHandler
+
+	module  *Module
+	library *libraryDecorator
+}
+
+func (h *libraryHeaderBazelHander) generateBazelBuildActions(ctx android.ModuleContext, label string) bool {
+	bazelCtx := ctx.Config().BazelContext
+	ccInfo, ok, err := bazelCtx.GetCcInfo(label, ctx.Arch().ArchType)
+	if err != nil {
+		ctx.ModuleErrorf("Error getting Bazel CcInfo: %s", err)
+		return false
+	}
+	if !ok {
+		return false
+	}
+
+	outputPaths := ccInfo.OutputFiles
+	if len(outputPaths) != 1 {
+		ctx.ModuleErrorf("expected exactly one output file for %q, but got %q", label, outputPaths)
+		return false
+	}
+
+	outputPath := android.PathForBazelOut(ctx, outputPaths[0])
+	h.module.outputFile = android.OptionalPathForPath(outputPath)
+
+	// HeaderLibraryInfo is an empty struct to indicate to dependencies that this is a header library
+	ctx.SetProvider(HeaderLibraryInfoProvider, HeaderLibraryInfo{})
+
+	flagExporterInfo := flagExporterInfoFromCcInfo(ctx, ccInfo)
+	// Store flag info to be passed along to androimk
+	// TODO(b/184387147): Androidmk should be done in Bazel, not Soong.
+	h.library.flagExporterInfo = &flagExporterInfo
+	// flag exporters consolidates properties like includes, flags, dependencies that should be
+	// exported from this module to other modules
+	ctx.SetProvider(FlagExporterInfoProvider, flagExporterInfo)
+
+	// Dependencies on this library will expect collectedSnapshotHeaders to be set, otherwise
+	// validation will fail. For now, set this to an empty list.
+	// TODO(cparsons): More closely mirror the collectHeadersForSnapshot implementation.
+	h.library.collectedSnapshotHeaders = android.Paths{}
+
+	return true
+}
+
 // cc_library_headers contains a set of c/c++ headers which are imported by
 // other soong cc modules using the header_libs property. For best practices,
 // use export_include_dirs property or LOCAL_EXPORT_C_INCLUDE_DIRS for
@@ -51,6 +97,7 @@ func LibraryHeaderFactory() android.Module {
 	module, library := NewLibrary(android.HostAndDeviceSupported)
 	library.HeaderOnly()
 	module.sdkMemberTypes = []android.SdkMemberType{headersLibrarySdkMemberType}
+	module.bazelHandler = &libraryHeaderBazelHander{module: module, library: library}
 	return module.Init()
 }