Add a target modules dump ast command.

This is useful for investigating the clang ast as you reconstruct
it via by parsing debug info.  It can also be used to write tests
against.

Differential Revision: https://reviews.llvm.org/D54072

llvm-svn: 346149
diff --git a/lldb/source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.h b/lldb/source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.h
index c2b5729..94fa580 100644
--- a/lldb/source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.h
+++ b/lldb/source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.h
@@ -155,6 +155,8 @@
   ClangASTContext &GetASTContext() { return *m_clang; }
   ClangASTImporter &GetASTImporter() { return *m_importer; }
 
+  void DumpClangAST(Stream &s) override;
+
 private:
   size_t FindTypesByName(llvm::StringRef name, uint32_t max_matches,
                          TypeMap &types);