One more batch of self-containing headers.

llvm-svn: 258974
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfFile.h b/llvm/lib/CodeGen/AsmPrinter/DwarfFile.h
index 8402027..291319c 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfFile.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfFile.h
@@ -16,6 +16,7 @@
 #include "llvm/ADT/FoldingSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringMap.h"
+#include "llvm/IR/Metadata.h"
 #include "llvm/Support/Allocator.h"
 #include <memory>
 #include <string>