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/sdk.go b/java/sdk.go
index 5d79d1d..fa4c053 100644
--- a/java/sdk.go
+++ b/java/sdk.go
@@ -53,7 +53,7 @@
 
 func UseApiFingerprint(ctx android.BaseModuleContext) bool {
 	if ctx.Config().UnbundledBuild() &&
-		!ctx.Config().UnbundledBuildUsePrebuiltSdks() &&
+		!ctx.Config().AlwaysUsePrebuiltSdks() &&
 		ctx.Config().IsEnvTrue("UNBUNDLED_BUILD_TARGET_SDK_WITH_API_FINGERPRINT") {
 		return true
 	}
@@ -212,7 +212,7 @@
 func (s sdkSpec) usePrebuilt(ctx android.EarlyModuleContext) bool {
 	if s.version.isCurrent() {
 		// "current" can be built from source and be from prebuilt SDK
-		return ctx.Config().UnbundledBuildUsePrebuiltSdks()
+		return ctx.Config().AlwaysUsePrebuiltSdks()
 	} else if s.version.isNumbered() {
 		// validation check
 		if s.kind != sdkPublic && s.kind != sdkSystem && s.kind != sdkTest {
@@ -511,7 +511,7 @@
 type sdkSingleton struct{}
 
 func (sdkSingleton) GenerateBuildActions(ctx android.SingletonContext) {
-	if ctx.Config().UnbundledBuildUsePrebuiltSdks() || ctx.Config().IsPdkBuild() {
+	if ctx.Config().AlwaysUsePrebuiltSdks() || ctx.Config().IsPdkBuild() {
 		return
 	}
 
@@ -634,7 +634,7 @@
 	} else if ctx.Config().IsPdkBuild() {
 		// TODO: get this from the PDK artifacts?
 		cmd.Text("echo PDK >").Output(out)
-	} else if !ctx.Config().UnbundledBuildUsePrebuiltSdks() {
+	} else if !ctx.Config().AlwaysUsePrebuiltSdks() {
 		in, err := ctx.GlobWithDeps("frameworks/base/api/*current.txt", nil)
 		if err != nil {
 			ctx.Errorf("error globbing API files: %s", err)
@@ -663,7 +663,7 @@
 }
 
 func sdkMakeVars(ctx android.MakeVarsContext) {
-	if ctx.Config().UnbundledBuildUsePrebuiltSdks() || ctx.Config().IsPdkBuild() {
+	if ctx.Config().AlwaysUsePrebuiltSdks() || ctx.Config().IsPdkBuild() {
 		return
 	}