DevTools: make InspectorDebuggerAgent aggregate V8DebuggerAgent instead of inheriting

Source/core/inspector/WorkerDebuggerAgent.cpp

 /*
  * 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 43 matching lines @@
 }
 
 DEFINE_TRACE(WorkerDebuggerAgent)
 {
     visitor->trace(m_inspectedWorkerGlobalScope);
     InspectorDebuggerAgent::trace(visitor);
 }
 
 InjectedScript WorkerDebuggerAgent::defaultInjectedScript()
 {
-    return injectedScriptManager()->injectedScriptFor(m_inspectedWorkerGlobalScope->script()->scriptState());
+    return m_debuggerAgent->injectedScriptManager()->injectedScriptFor(m_inspectedWorkerGlobalScope->script()->scriptState());
 }
 
 void WorkerDebuggerAgent::muteConsole()
 {
     // We don't need to mute console for workers.
 }
 
 void WorkerDebuggerAgent::unmuteConsole()
 {
     // We don't need to mute console for workers.
 }
 
 } // namespace blink