GC plugin: split out reporting of errors/warnings.

tools/clang/blink_gc_plugin/CheckFieldsVisitor.h

 // Copyright 2015 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.
 
 #ifndef TOOLS_BLINK_GC_PLUGIN_CHECK_FIELDS_VISITOR_H_
 #define TOOLS_BLINK_GC_PLUGIN_CHECK_FIELDS_VISITOR_H_
 
 #include <vector>
 
 #include "Edge.h"
@@ skipping 13 matching lines @@
     kRawPtrToGCManaged,
     kRefPtrToGCManaged,
     kReferencePtrToGCManaged,
     kOwnPtrToGCManaged,
     kMemberToGCUnmanaged,
     kMemberInUnmanaged,
     kPtrFromHeapToStack,
     kGCDerivedPartObject
   };
 
-  typedef std::vector<std::pair<FieldPoint*, Error> > Errors;
+  using Errors = std::vector<std::pair<FieldPoint*, Error>>;
 
-  explicit CheckFieldsVisitor(const BlinkGCPluginOptions& options);
+  CheckFieldsVisitor();
 
   Errors& invalid_fields();
 
   bool ContainsInvalidFields(RecordInfo* info);
 
   void AtMember(Member* edge) override;
   void AtValue(Value* edge) override;
   void AtCollection(Collection* edge) override;
 
  private:
   Error InvalidSmartPtr(Edge* ptr);
 
-  const BlinkGCPluginOptions& options_;
   FieldPoint* current_;
   bool stack_allocated_host_;
   bool managed_host_;
   Errors invalid_fields_;
 };
 
 #endif  // TOOLS_BLINK_GC_PLUGIN_CHECK_FIELDS_VISITOR_H_