Refactor vendor snapshot to use LinkableInterface.

Refactors the vendor snapshot support to use the LinkableInterface
so that support can be extended to Rust. This CL does not add
vendor snapshot support for Rust; that is left for a follow-on CL.

Bug: 184042776
Test: m nothing
Change-Id: Id0c4970ca00053484a52677d182153cbc454c301
diff --git a/cc/vndk.go b/cc/vndk.go
index 8b3788b..0254edc 100644
--- a/cc/vndk.go
+++ b/cc/vndk.go
@@ -372,7 +372,7 @@
 			if mctx.ModuleName() == "libz" {
 				return false
 			}
-			return m.ImageVariation().Variation == android.CoreVariation && lib.shared() && m.isVndkSp()
+			return m.ImageVariation().Variation == android.CoreVariation && lib.shared() && m.IsVndkSp()
 		}
 
 		useCoreVariant := m.VndkVersion() == mctx.DeviceConfig().PlatformVndkVersion() &&
@@ -574,38 +574,37 @@
 	vndkSnapshotZipFile android.OptionalPath
 }
 
-func isVndkSnapshotAware(config android.DeviceConfig, m *Module,
-	apexInfo android.ApexInfo) (i snapshotLibraryInterface, vndkType string, isVndkSnapshotLib bool) {
+func isVndkSnapshotAware(config android.DeviceConfig, m LinkableInterface,
+	apexInfo android.ApexInfo) (vndkType string, isVndkSnapshotLib bool) {
 
 	if m.Target().NativeBridge == android.NativeBridgeEnabled {
-		return nil, "", false
+		return "", false
 	}
 	// !inVendor: There's product/vendor variants for VNDK libs. We only care about vendor variants.
 	// !installable: Snapshot only cares about "installable" modules.
 	// !m.IsLlndk: llndk stubs are required for building against snapshots.
 	// IsSnapshotPrebuilt: Snapshotting a snapshot doesn't make sense.
 	// !outputFile.Valid: Snapshot requires valid output file.
-	if !m.InVendor() || (!m.installable(apexInfo) && !m.IsLlndk()) || m.IsSnapshotPrebuilt() || !m.outputFile.Valid() {
-		return nil, "", false
+	if !m.InVendor() || (!installable(m, apexInfo) && !m.IsLlndk()) || m.IsSnapshotPrebuilt() || !m.OutputFile().Valid() {
+		return "", false
 	}
-	l, ok := m.linker.(snapshotLibraryInterface)
-	if !ok || !l.shared() {
-		return nil, "", false
+	if !m.IsSnapshotLibrary() || !m.Shared() {
+		return "", false
 	}
 	if m.VndkVersion() == config.PlatformVndkVersion() {
 		if m.IsVndk() && !m.IsVndkExt() {
-			if m.isVndkSp() {
-				return l, "vndk-sp", true
+			if m.IsVndkSp() {
+				return "vndk-sp", true
 			} else {
-				return l, "vndk-core", true
+				return "vndk-core", true
 			}
-		} else if l.hasLLNDKStubs() && l.stubsVersion() == "" {
+		} else if m.HasLlndkStubs() && m.StubsVersion() == "" {
 			// Use default version for the snapshot.
-			return l, "llndk-stub", true
+			return "llndk-stub", true
 		}
 	}
 
-	return nil, "", false
+	return "", false
 }
 
 func (c *vndkSnapshotSingleton) GenerateBuildActions(ctx android.SingletonContext) {
@@ -722,7 +721,7 @@
 
 		apexInfo := ctx.ModuleProvider(module, android.ApexInfoProvider).(android.ApexInfo)
 
-		l, vndkType, ok := isVndkSnapshotAware(ctx.DeviceConfig(), m, apexInfo)
+		vndkType, ok := isVndkSnapshotAware(ctx.DeviceConfig(), m, apexInfo)
 		if !ok {
 			return
 		}
@@ -761,7 +760,7 @@
 		}
 
 		if ctx.Config().VndkSnapshotBuildArtifacts() {
-			headers = append(headers, l.snapshotHeaders()...)
+			headers = append(headers, m.SnapshotHeaders()...)
 		}
 	})