Split Java libraries per apex

Just like native libs, a java library that is included in an APEX is
mutated for the APEX. This allows us to infer the context (e.g.
sdk_version, etc.) for building a java library in an APEX.

Bug: 138182343
Test: apex_test added
Change-Id: I9292ea097b98e74a8a794f164bd2bed3921d6337
diff --git a/java/androidmk.go b/java/androidmk.go
index 90fdd0f..ad0e171 100644
--- a/java/androidmk.go
+++ b/java/androidmk.go
@@ -55,6 +55,11 @@
 }
 
 func (library *Library) AndroidMk() android.AndroidMkData {
+	if !library.IsForPlatform() {
+		return android.AndroidMkData{
+			Disabled: true,
+		}
+	}
 	return android.AndroidMkData{
 		Class:      "JAVA_LIBRARIES",
 		OutputFile: android.OptionalPathForPath(library.outputFile),
@@ -141,6 +146,11 @@
 }
 
 func (prebuilt *Import) AndroidMk() android.AndroidMkData {
+	if !prebuilt.IsForPlatform() {
+		return android.AndroidMkData{
+			Disabled: true,
+		}
+	}
 	return android.AndroidMkData{
 		Class:      "JAVA_LIBRARIES",
 		OutputFile: android.OptionalPathForPath(prebuilt.combinedClasspathFile),
@@ -157,6 +167,11 @@
 }
 
 func (prebuilt *DexImport) AndroidMk() android.AndroidMkData {
+	if !prebuilt.IsForPlatform() {
+		return android.AndroidMkData{
+			Disabled: true,
+		}
+	}
 	return android.AndroidMkData{
 		Class:      "JAVA_LIBRARIES",
 		OutputFile: android.OptionalPathForPath(prebuilt.maybeStrippedDexJarFile),