[clang-tidy] Make ClangTidyCheck::OptionsView public.

[ymandel]

Summary

The OptionsView class is currently protected. This constraint prevents tidies from passing the OptionsView to, for example, a helper function. Similarly, TransformerClangTidyCheck cannot pass the OptionsView object to functions that generate tooling::RewriteRules. The latter is needed to allow the definition of such rules to depend on the clang-tidy options, as demonstrated in the child revision.

clang-tools-extra/clang-tidy/ClangTidyCheck.h

public:
 
   /// \brief Should store all options supported by this check with their
   /// current values or default values for options that haven't been overridden.
   ///
   /// The check should use ``Options.store()`` to store each option it supports
   /// whether it has the default value or it has been overridden.
   virtual void storeOptions(ClangTidyOptions::OptionMap &Options) {}
 
-private:
-  void run(const ast_matchers::MatchFinder::MatchResult &Result) override;
-  StringRef getID() const override { return CheckName; }
-  std::string CheckName;
-  ClangTidyContext *Context;
-
-protected:
   /// \brief Provides access to the ``ClangTidyCheck`` options via check-local
   /// names.
   ///
   /// Methods of this class prepend ``CheckName + "."`` to translate check-local
   /// option names to global option names.
   class OptionsView {
   public:
     /// \brief Initializes the instance using \p CheckName + "." as a prefix.
public:
     void store(ClangTidyOptions::OptionMap &Options, StringRef LocalName,
                int64_t Value) const;
 
   private:
     std::string NamePrefix;
     const ClangTidyOptions::OptionMap &CheckOptions;
   };
 
+private:
+  void run(const ast_matchers::MatchFinder::MatchResult &Result) override;
+  StringRef getID() const override { return CheckName; }
+  std::string CheckName;
+  ClangTidyContext *Context;
+
+protected:
   OptionsView Options;
   /// \brief Returns the main file name of the current translation unit.
   StringRef getCurrentMainFile() const { return Context->getCurrentFile(); }
   /// \brief Returns the language options from the context.
   const LangOptions &getLangOpts() const { return Context->getLangOpts(); }
 };
 
 } // namespace tidy
 } // namespace clang
 
 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CLANGTIDYCHECK_H