abstract-filter: provide default handleDef() implementation

... in GenericAbstractFilter to avoid duplicated code in its derivates.

No changes in behavior intended by this change.

Author: kdudka

src/abstract-filter.hh

@@ -41,6 +41,10 @@ class GenericAbstractFilter: public AbstractWriter {
 
         ~GenericAbstractFilter() override = default;
 
+        void handleDef(const Defect &def) override {
+            agent_->handleDef(def);
+        }
+
         void flush() override {
             agent_->flush();
         }

src/csgrep.cc

@@ -384,12 +384,6 @@ class DropScanProps: public GenericAbstractFilter {
             return emp_;
         }
 
-    protected:
-        /// trivial pass-through
-        void handleDef(const Defect &def) override {
-            agent_->handleDef(def);
-        }
-
     private:
         const TScanProps emp_;
 };