Remove unused plugin argument to skip virtual method checks in .cc files

tools/clang/plugins/Options.h

Index: tools/clang/plugins/Options.h
diff --git a/tools/clang/plugins/Options.h b/tools/clang/plugins/Options.h
index bb50124d57f371973738aef5dc5dfacbbdcc1f93..82dfafb645bf2bed4e3f4b1938e47de904b49287 100644
--- a/tools/clang/plugins/Options.h
+++ b/tools/clang/plugins/Options.h
@@ -10,12 +10,10 @@ namespace chrome_checker {
 struct Options {
   Options()
       : check_base_classes(false),
-        check_virtuals_in_implementations(true),
         check_weak_ptr_factory_order(false),
         check_enum_last_value(false) {}
 
   bool check_base_classes;
-  bool check_virtuals_in_implementations;
   bool check_weak_ptr_factory_order;
   bool check_enum_last_value;
 };