Remove raw values from proto APK

Raw attribute values are not included in xml files when building binary
APKs but they are when building proto APKs. Remove raw attribute values
and create a new convert flag that (--keep-raw-values) that allows raw
value to be kept.

Also added flag to link to keep raw attribute values.

Bug: 115915884
Bug: 116700688
Test: aapt2_tests
Change-Id: Id50136b775b3f43d159ca06181282f6a7b8eaf40
diff --git a/tools/aapt2/util/Files.cpp b/tools/aapt2/util/Files.cpp
index 5cfbbf2..7b268bb 100644
--- a/tools/aapt2/util/Files.cpp
+++ b/tools/aapt2/util/Files.cpp
@@ -180,6 +180,17 @@
   base->append(part.data(), part.size());
 }
 
+std::string BuildPath(std::vector<const StringPiece>&& args) {
+  if (args.empty()) {
+    return "";
+  }
+  std::string out = args[0].to_string();
+  for (int i = 1; i < args.size(); i++) {
+    file::AppendPath(&out, args[i]);
+  }
+  return out;
+}
+
 std::string PackageToPath(const StringPiece& package) {
   std::string out_path;
   for (const StringPiece& part : util::Tokenize(package, '.')) {