Support NDK variant of cc_api_variant

Update cc build logic to support NDK variant of cc_api_variant. Any
cc_api_library with NDK variant of cc_api_variant would be treated as
similar with NDK library.

Bug: 259007436
Test: Cuttlefish vendor build succeeded
Change-Id: I75a7475f4fdcbac779f5aa64e76c60f94ea7ea1a
diff --git a/cc/sdk.go b/cc/sdk.go
index a0d196b..3e50c9f 100644
--- a/cc/sdk.go
+++ b/cc/sdk.go
@@ -31,6 +31,7 @@
 
 	switch m := ctx.Module().(type) {
 	case LinkableInterface:
+		ccModule, isCcModule := ctx.Module().(*Module)
 		if m.AlwaysSdk() {
 			if !m.UseSdk() && !m.SplitPerApiLevel() {
 				ctx.ModuleErrorf("UseSdk() must return true when AlwaysSdk is set, did the factory forget to set Sdk_version?")
@@ -58,11 +59,32 @@
 				modules[1].(*Module).Properties.PreventInstall = true
 			}
 			ctx.AliasVariation("")
+		} else if isCcModule && ccModule.isImportedApiLibrary() {
+			apiLibrary, _ := ccModule.linker.(*apiLibraryDecorator)
+			if apiLibrary.hasNDKStubs() && ccModule.canUseSdk() {
+				// Handle cc_api_library module with NDK stubs and variants only which can use SDK
+				modules := ctx.CreateVariations("", "sdk")
+				modules[1].(*Module).Properties.IsSdkVariant = true
+				if ctx.Config().UnbundledBuildApps() {
+					// For an unbundled apps build, hide the platform variant from Make.
+					modules[0].(*Module).Properties.HideFromMake = true
+					modules[0].(*Module).Properties.PreventInstall = true
+				} else {
+					// For a platform build, mark the SDK variant so that it gets a ".sdk" suffix when
+					// exposed to Make.
+					modules[1].(*Module).Properties.SdkAndPlatformVariantVisibleToMake = true
+					modules[1].(*Module).Properties.PreventInstall = true
+				}
+			} else {
+				ccModule.Properties.Sdk_version = nil
+				ctx.CreateVariations("")
+				ctx.AliasVariation("")
+			}
 		} else {
-			if m, ok := ctx.Module().(*Module); ok {
+			if isCcModule {
 				// Clear the sdk_version property for modules that don't have an SDK variant so
 				// later code doesn't get confused by it.
-				m.Properties.Sdk_version = nil
+				ccModule.Properties.Sdk_version = nil
 			}
 			ctx.CreateVariations("")
 			ctx.AliasVariation("")
@@ -79,6 +101,11 @@
 	case *snapshotModule:
 		ctx.CreateVariations("")
 	case *CcApiVariant:
-		ctx.CreateVariations("")
+		ccApiVariant, _ := ctx.Module().(*CcApiVariant)
+		if String(ccApiVariant.properties.Variant) == "ndk" {
+			ctx.CreateVariations("sdk")
+		} else {
+			ctx.CreateVariations("")
+		}
 	}
 }