DevTools: make InspectorDebuggerAgent aggregate V8DebuggerAgent instead of inheriting

Source/core/inspector/InspectorBaseAgent.h

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 84 matching lines @@
     RawPtrWillBeMember<InstrumentingAgents> m_instrumentingAgents;
     RawPtrWillBeMember<InspectorCompositeState> m_inspectorState;
     WillBeHeapVector<OwnPtrWillBeMember<InspectorAgent> > m_agents;
 };
 
 template<typename AgentClass, typename FrontendClass>
 class InspectorBaseAgent : public InspectorAgent {
 public:
     ~InspectorBaseAgent() override { }
 
-    void setFrontend(InspectorFrontend* frontend) final
+    void setFrontend(InspectorFrontend* frontend) override
     {
         ASSERT(!m_frontend);
         m_frontend = FrontendClass::from(frontend);
     }
 
-    void clearFrontend() final
+    void clearFrontend() override
     {
         ErrorString error;
         disable(&error);
         ASSERT(m_frontend);
         m_frontend = nullptr;
     }
 
     void registerInDispatcher(InspectorBackendDispatcher* dispatcher) final
     {
         dispatcher->registerAgent(static_cast<AgentClass*>(this));
@@ skipping 13 matching lines @@
 };
 
 inline bool asBool(const bool* const b)
 {
     return b ? *b : false;
 }
 
 } // namespace blink
 
 #endif // !defined(InspectorBaseAgent_h)