Do not disable V8's LiveEdit on startup.

third_party/WebKit/Source/bindings/core/v8/V8Initializer.cpp

 /*
  * Copyright (C) 2009 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 359 matching lines @@
 static void initializeV8Common(v8::Isolate* isolate) {
   isolate->AddGCPrologueCallback(V8GCController::gcPrologue);
   isolate->AddGCEpilogueCallback(V8GCController::gcEpilogue);
   std::unique_ptr<ScriptWrappableVisitor> visitor(
       new ScriptWrappableVisitor(isolate));
   V8PerIsolateData::from(isolate)->setScriptWrappableVisitor(
       std::move(visitor));
   isolate->SetEmbedderHeapTracer(
       V8PerIsolateData::from(isolate)->scriptWrappableVisitor());
 
-  v8::Debug::SetLiveEditEnabled(isolate, false);
-
   isolate->SetMicrotasksPolicy(v8::MicrotasksPolicy::kScoped);
 
   isolate->SetUseCounterCallback(&useCounterCallback);
 }
 
 namespace {
 
 class ArrayBufferAllocator : public v8::ArrayBuffer::Allocator {
   // Allocate() methods return null to signal allocation failure to V8, which
   // should respond by throwing a RangeError, per
@@ skipping 168 matching lines @@
           v8::Isolate::kMessageLog);
   isolate->SetFatalErrorHandler(reportFatalErrorInWorker);
 
   uint32_t here;
   isolate->SetStackLimit(reinterpret_cast<uintptr_t>(&here) -
                          kWorkerMaxStackSize);
   isolate->SetPromiseRejectCallback(promiseRejectHandlerInWorker);
 }
 
 }  // namespace blink