For consistency, use llvm::raw_ostream in the rest of the mangle api.

llvm-svn: 125360
diff --git a/clang/lib/CodeGen/CGVTT.cpp b/clang/lib/CodeGen/CGVTT.cpp
index 604e4cb..78b2dbe 100644
--- a/clang/lib/CodeGen/CGVTT.cpp
+++ b/clang/lib/CodeGen/CGVTT.cpp
@@ -393,7 +393,9 @@
   assert(RD->getNumVBases() && "Only classes with virtual bases need a VTT");
 
   llvm::SmallString<256> OutName;
-  CGM.getCXXABI().getMangleContext().mangleCXXVTT(RD, OutName);
+  llvm::raw_svector_ostream Out(OutName);
+  CGM.getCXXABI().getMangleContext().mangleCXXVTT(RD, Out);
+  Out.flush();
   llvm::StringRef Name = OutName.str();
 
   VTTBuilder Builder(CGM, RD, /*GenerateDefinition=*/false);