Introduce AlwaysUsePrebuiltSdks

Instead of UnbundledBuild, use AlwaysUsePrebuiltSdks
to determine if java modules needs to be built against prebuilt sdks.
And rename UnbundledBuildUsePrebuiltSdks to AlwaysUsePrebuiltSdks to
express its behavior more correctly.(It can be orthgonal to "Unbundled")

Bug: 160390776
Test: TARGET_BUILD_UNBUNDLED_IMAGE=true m vendorimage

Change-Id: I0be7265c1959d8774c295372cd7a9250169f6df9
diff --git a/java/config/config.go b/java/config/config.go
index d2f4513..d0296ff 100644
--- a/java/config/config.go
+++ b/java/config/config.go
@@ -128,7 +128,7 @@
 	pctx.HostBinToolVariable("ExtractApksCmd", "extract_apks")
 	pctx.VariableFunc("TurbineJar", func(ctx android.PackageVarContext) string {
 		turbine := "turbine.jar"
-		if ctx.Config().UnbundledBuild() {
+		if ctx.Config().AlwaysUsePrebuiltSdks() {
 			return "prebuilts/build-tools/common/framework/" + turbine
 		} else {
 			return ctx.Config().HostJavaToolPath(ctx, turbine).String()
@@ -178,7 +178,7 @@
 
 func hostBinToolVariableWithSdkToolsPrebuilt(name, tool string) {
 	pctx.VariableFunc(name, func(ctx android.PackageVarContext) string {
-		if ctx.Config().UnbundledBuild() || ctx.Config().IsPdkBuild() {
+		if ctx.Config().AlwaysUsePrebuiltSdks() || ctx.Config().IsPdkBuild() {
 			return filepath.Join("prebuilts/sdk/tools", runtime.GOOS, "bin", tool)
 		} else {
 			return ctx.Config().HostToolPath(ctx, tool).String()
@@ -188,7 +188,7 @@
 
 func hostJavaToolVariableWithSdkToolsPrebuilt(name, tool string) {
 	pctx.VariableFunc(name, func(ctx android.PackageVarContext) string {
-		if ctx.Config().UnbundledBuild() || ctx.Config().IsPdkBuild() {
+		if ctx.Config().AlwaysUsePrebuiltSdks() || ctx.Config().IsPdkBuild() {
 			return filepath.Join("prebuilts/sdk/tools/lib", tool+".jar")
 		} else {
 			return ctx.Config().HostJavaToolPath(ctx, tool+".jar").String()
@@ -198,7 +198,7 @@
 
 func hostJNIToolVariableWithSdkToolsPrebuilt(name, tool string) {
 	pctx.VariableFunc(name, func(ctx android.PackageVarContext) string {
-		if ctx.Config().UnbundledBuild() || ctx.Config().IsPdkBuild() {
+		if ctx.Config().AlwaysUsePrebuiltSdks() || ctx.Config().IsPdkBuild() {
 			ext := ".so"
 			if runtime.GOOS == "darwin" {
 				ext = ".dylib"
@@ -212,7 +212,7 @@
 
 func hostBinToolVariableWithBuildToolsPrebuilt(name, tool string) {
 	pctx.VariableFunc(name, func(ctx android.PackageVarContext) string {
-		if ctx.Config().UnbundledBuild() || ctx.Config().IsPdkBuild() {
+		if ctx.Config().AlwaysUsePrebuiltSdks() || ctx.Config().IsPdkBuild() {
 			return filepath.Join("prebuilts/build-tools", ctx.Config().PrebuiltOS(), "bin", tool)
 		} else {
 			return ctx.Config().HostToolPath(ctx, tool).String()