Set ApkAssets path for fabricated rros

Fabricated RROs do not provide assets but are stored on disk. Ensure
that the path to the frro is returned when querying for the ApkAssets
path (which is mostly for debug purposes).

Bug: 181338216
Test: enable frro, use cmd overlay lookup to see path in resolution
Change-Id: Ibf9b1bf0a995325affbf084c71b1e87c5682e734
diff --git a/libs/androidfw/AssetsProvider.cpp b/libs/androidfw/AssetsProvider.cpp
index 0aaf0b3..6c7a253 100644
--- a/libs/androidfw/AssetsProvider.cpp
+++ b/libs/androidfw/AssetsProvider.cpp
@@ -386,8 +386,15 @@
   return primary_->IsUpToDate() && secondary_->IsUpToDate();
 }
 
+EmptyAssetsProvider::EmptyAssetsProvider(std::optional<std::string>&& path) :
+    path_(std::move(path)) {}
+
 std::unique_ptr<AssetsProvider> EmptyAssetsProvider::Create() {
-  return std::make_unique<EmptyAssetsProvider>();
+  return std::unique_ptr<EmptyAssetsProvider>(new EmptyAssetsProvider({}));
+}
+
+std::unique_ptr<AssetsProvider> EmptyAssetsProvider::Create(const std::string& path) {
+  return std::unique_ptr<EmptyAssetsProvider>(new EmptyAssetsProvider(path));
 }
 
 std::unique_ptr<Asset> EmptyAssetsProvider::OpenInternal(const std::string& /* path */,
@@ -406,10 +413,16 @@
 }
 
 std::optional<std::string_view> EmptyAssetsProvider::GetPath() const {
+  if (path_.has_value()) {
+    return *path_;
+  }
   return {};
 }
 
 const std::string& EmptyAssetsProvider::GetDebugName() const {
+  if (path_.has_value()) {
+    return *path_;
+  }
   const static std::string kEmpty = kEmptyDebugString;
   return kEmpty;
 }