Clang style plugin: add warn-only option and use it on Windows

tools/clang/plugins/FindBadConstructsConsumer.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file defines a bunch of recurring problems in the Chromium C++ code.
 //
 // Checks that are implemented:
 // - Constructors/Destructors should not be inlined if they are of a complex
 //   class type.
 // - Missing "virtual" keywords on methods that should be virtual.
@@ skipping 53 matching lines @@
   void CheckVirtualBodies(const clang::CXXMethodDecl* method);
 
   void CountType(const clang::Type* type,
                  int* trivial_member,
                  int* non_trivial_member,
                  int* templated_non_trivial_member);
 
   static RefcountIssue CheckRecordForRefcountIssue(
       const clang::CXXRecordDecl* record,
       clang::SourceLocation& loc);
-  clang::DiagnosticsEngine::Level getErrorLevel();
   static bool IsRefCountedCallback(const clang::CXXBaseSpecifier* base,
                                    clang::CXXBasePath& path,
                                    void* user_data);
   static bool HasPublicDtorCallback(const clang::CXXBaseSpecifier* base,
                                     clang::CXXBasePath& path,
                                     void* user_data);
   void PrintInheritanceChain(const clang::CXXBasePath& path);
   unsigned DiagnosticForIssue(RefcountIssue issue);
   void CheckRefCountedDtors(clang::SourceLocation record_location,
                             clang::CXXRecordDecl* record);
 
   void CheckWeakPtrFactoryMembers(clang::SourceLocation record_location,
                                   clang::CXXRecordDecl* record);
 
-  const Options options_;
-
   unsigned diag_method_requires_override_;
   unsigned diag_redundant_virtual_specifier_;
   unsigned diag_base_method_virtual_and_final_;
   unsigned diag_no_explicit_dtor_;
   unsigned diag_public_dtor_;
   unsigned diag_protected_non_virtual_dtor_;
   unsigned diag_weak_ptr_factory_order_;
   unsigned diag_bad_enum_last_value_;
   unsigned diag_note_inheritance_;
   unsigned diag_note_implicit_dtor_;
   unsigned diag_note_public_dtor_;
   unsigned diag_note_protected_non_virtual_dtor_;
 };
 
 }  // namespace chrome_checker