Factor out gin::IsolateHolder's constructor

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 379 matching lines @@
                           : gin::IsolateHolder::kStableV8Extras;
   gin::IsolateHolder::Initialize(gin::IsolateHolder::kNonStrictMode,
                                  v8ExtrasMode, &arrayBufferAllocator);
 
   // NOTE: Some threads (namely utility threads) don't have a scheduler.
   WebScheduler* scheduler = Platform::current()->currentThread()->scheduler();
   // When timer task runner is used for PerIsolateData, GC tasks are getting
   // throttled and memory usage goes up. For now we're using loading task queue
   // to prevent this.
   // TODO(altimin): Consider switching to timerTaskRunner here.
-  v8::Isolate* isolate = V8PerIsolateData::initialize(
+
+  WebTaskRunner* taskRunner =
       scheduler ? scheduler->loadingTaskRunner()
-                : Platform::current()->currentThread()->getWebTaskRunner());
+                : Platform::current()->currentThread()->getWebTaskRunner();
+  std::unique_ptr<gin::IsolateHolder> isolateHolder(
+      WTF::makeUnique<gin::IsolateHolder>(
+          taskRunner ? taskRunner->toSingleThreadTaskRunner() : nullptr,
+          gin::IsolateHolder::kSingleThread,
+          isMainThread() ? gin::IsolateHolder::kDisallowAtomicsWait
+                         : gin::IsolateHolder::kAllowAtomicsWait));
+  v8::Isolate* isolate = V8PerIsolateData::initialize(std::move(isolateHolder));
 
   initializeV8Common(isolate);
 
   isolate->SetOOMErrorHandler(reportOOMErrorInMainThread);
   isolate->SetFatalErrorHandler(reportFatalErrorInMainThread);
   isolate->AddMessageListenerWithErrorLevel(
       messageHandlerInMainThread,
       v8::Isolate::kMessageError | v8::Isolate::kMessageWarning |
           v8::Isolate::kMessageInfo | v8::Isolate::kMessageDebug |
           v8::Isolate::kMessageLog);
@@ skipping 101 matching lines @@
           v8::Isolate::kMessageLog);
   isolate->SetFatalErrorHandler(reportFatalErrorInWorker);
 
   uint32_t here;
   isolate->SetStackLimit(reinterpret_cast<uintptr_t>(&here) -
                          kWorkerMaxStackSize);
   isolate->SetPromiseRejectCallback(promiseRejectHandlerInWorker);
 }
 
 }  // namespace blink