[AST] Let DeclarationNameInfo printing use PrintingPolicy, and fix const-correctness
diff --git a/clang/lib/AST/DeclPrinter.cpp b/clang/lib/AST/DeclPrinter.cpp
index 2c0077e..a11c876 100644
--- a/clang/lib/AST/DeclPrinter.cpp
+++ b/clang/lib/AST/DeclPrinter.cpp
@@ -625,13 +625,13 @@
   if (Policy.FullyQualifiedName) {
     Proto += D->getQualifiedNameAsString();
   } else {
+    llvm::raw_string_ostream OS(Proto);
     if (!Policy.SuppressScope) {
       if (const NestedNameSpecifier *NS = D->getQualifier()) {
-        llvm::raw_string_ostream OS(Proto);
         NS->print(OS, Policy);
       }
     }
-    Proto += D->getNameInfo().getAsString();
+    D->getNameInfo().printName(OS, Policy);
   }
 
   if (GuideDecl)