Constify the getClassName routine and variables that come out of it,
and then use it for forward decl names.

Part of rdar://10209967 and rdar://10400981

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@150040 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGDebugInfo.h b/lib/CodeGen/CGDebugInfo.h
index c2a28fd..c00c469 100644
--- a/lib/CodeGen/CGDebugInfo.h
+++ b/lib/CodeGen/CGDebugInfo.h
@@ -293,7 +293,7 @@
   StringRef getSelectorName(Selector S);
 
   /// getClassName - Get class name including template argument list.
-  StringRef getClassName(RecordDecl *RD);
+  StringRef getClassName(const RecordDecl *RD);
 
   /// getVTableName - Get vtable name for the given Class.
   StringRef getVTableName(const CXXRecordDecl *Decl);