AAPT2: Follow symlinks when compiling

Bug: 62144459
Test: make AaptSymlinkTest
Change-Id: Idb3ab1ece17c52bb4fd174ec4c08a9e173289e55
diff --git a/tools/aapt2/cmd/Link.cpp b/tools/aapt2/cmd/Link.cpp
index 24a687c..dd4b2ba 100644
--- a/tools/aapt2/cmd/Link.cpp
+++ b/tools/aapt2/cmd/Link.cpp
@@ -632,7 +632,7 @@
 static bool LoadStableIdMap(IDiagnostics* diag, const std::string& path,
                             std::unordered_map<ResourceName, ResourceId>* out_id_map) {
   std::string content;
-  if (!android::base::ReadFileToString(path, &content)) {
+  if (!android::base::ReadFileToString(path, &content, true /*follow_symlinks*/)) {
     diag->Error(DiagMessage(path) << "failed reading stable ID file");
     return false;
   }