AAPT2: Few tweaks to get shared-libraries working

Test: manual (building shared support library demo)
Change-Id: I4730645aa92ba1893baf67ffe35fbd4aac0f8e46
diff --git a/tools/aapt2/java/JavaClassGenerator.cpp b/tools/aapt2/java/JavaClassGenerator.cpp
index 9c0f13c..68bdb95 100644
--- a/tools/aapt2/java/JavaClassGenerator.cpp
+++ b/tools/aapt2/java/JavaClassGenerator.cpp
@@ -533,9 +533,14 @@
   std::unique_ptr<MethodDefinition> rewrite_method;
 
   // Generate an onResourcesLoaded() callback if requested.
-  if (options_.generate_rewrite_callback) {
+  if (options_.rewrite_callback_options) {
     rewrite_method =
         util::make_unique<MethodDefinition>("public static void onResourcesLoaded(int p)");
+    for (const std::string& package_to_callback :
+         options_.rewrite_callback_options.value().packages_to_callback) {
+      rewrite_method->AppendStatement(
+          StringPrintf("%s.R.onResourcesLoaded(p);", package_to_callback.data()));
+    }
   }
 
   for (const auto& package : table_->packages) {