DevTools: respond with error when Debugger command is sent to disabled debugger agent

Source/bindings/core/v8/ScriptDebugServer.h

 /*
  * Copyright (c) 2010, 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 115 matching lines @@
 protected:
     ScriptDebugServer(v8::Isolate*, PassOwnPtr<Client>);
 
     virtual void clearCompiledScripts();
 
     virtual ScriptDebugListener* getDebugListenerForContext(v8::Local<v8::Context>) = 0;
     virtual void runMessageLoopOnPause(v8::Local<v8::Context>) = 0;
     virtual void quitMessageLoopOnPause() = 0;
 
 private:
-    void ensureDebuggerScriptCompiled();
+    void compileDebuggerScript();
     v8::MaybeLocal<v8::Value> callDebuggerMethod(const char* functionName, int argc, v8::Local<v8::Value> argv[]);
     v8::Local<v8::Object> debuggerScriptLocal() const;
     void clearBreakpoints();
 
     void dispatchDidParseSource(ScriptDebugListener*, v8::Local<v8::Object> sourceObject, CompileResult);
 
     static void breakProgramCallback(const v8::FunctionCallbackInfo<v8::Value>&);
     void handleProgramBreak(ScriptState* pausedScriptState, v8::Local<v8::Object> executionState, v8::Local<v8::Value> exception, v8::Local<v8::Array> hitBreakpoints, bool isPromiseRejection = false);
     static void v8InterruptCallback(v8::Isolate*, void*);
     static void v8DebugEventCallback(const v8::Debug::EventDetails&);
@@ skipping 22 matching lines @@
     RefPtr<ScriptState> m_pausedScriptState;
     bool m_runningNestedMessageLoop;
     class ThreadSafeTaskQueue;
     OwnPtr<ThreadSafeTaskQueue> m_taskQueue;
 };
 
 } // namespace blink
 
 
 #endif // ScriptDebugServer_h