Use a reference instead of a pointer.

This makes using a std::unique_ptr in the caller more convenient.

llvm-svn: 214433
diff --git a/llvm/tools/llvm-dwarfdump/llvm-dwarfdump.cpp b/llvm/tools/llvm-dwarfdump/llvm-dwarfdump.cpp
index 414205a..33bb766 100644
--- a/llvm/tools/llvm-dwarfdump/llvm-dwarfdump.cpp
+++ b/llvm/tools/llvm-dwarfdump/llvm-dwarfdump.cpp
@@ -82,7 +82,7 @@
   }
   std::unique_ptr<ObjectFile> Obj = std::move(ObjOrErr.get());
 
-  std::unique_ptr<DIContext> DICtx(DIContext::getDWARFContext(Obj.get()));
+  std::unique_ptr<DIContext> DICtx(DIContext::getDWARFContext(*Obj));
 
   outs() << Filename
          << ":\tfile format " << Obj->getFileFormatName() << "\n\n";