Fix -Wmismatched-tags introduced in r363910

That commit changed DIERef from a struct to a class, but did not update
the forward-declarations. This fixes one forward-declaration, and
removes other (unused) decls.

llvm-svn: 363915

lldb/source/Plugins/SymbolFile/DWARF/DWARFBaseDIE.h

@@ -12,14 +12,13 @@
 #include "lldb/Core/dwarf.h"
 #include "lldb/lldb-types.h"
 
-struct DIERef;
+class DIERef;
 class DWARFASTParser;
 class DWARFAttributes;
 class DWARFUnit;
 class DWARFDebugInfoEntry;
 class DWARFDeclContext;
 class SymbolFileDWARF;
-class DWARFDIE;
 
 class DWARFBaseDIE {
 public:

lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h

@@ -62,7 +62,6 @@ public:
   friend class SymbolFileDWARFDebugMap;
   friend class SymbolFileDWARFDwo;
   friend class DebugMapModule;
-  friend struct DIERef;
   friend class DWARFCompileUnit;
   friend class DWARFDIE;
   friend class DWARFASTParserClang;

lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.h

@@ -133,7 +133,6 @@ protected:
   enum { kHaveInitializedOSOs = (1 << 0), kNumFlags };
 
   friend class DebugMapModule;
-  friend struct DIERef;
   friend class DWARFASTParserClang;
   friend class DWARFCompileUnit;
   friend class SymbolFileDWARF;