Introduce infrastructure for tracing ScriptWrappables.

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 302 matching lines @@
         if (ContentSecurityPolicy* policy = toDocument(executionContext)->contentSecurityPolicy())
             return policy->allowEval(ScriptState::from(context), ContentSecurityPolicy::SendReport, ContentSecurityPolicy::WillThrowException);
     }
     return false;
 }
 
 static void initializeV8Common(v8::Isolate* isolate)
 {
     isolate->AddGCPrologueCallback(V8GCController::gcPrologue);
     isolate->AddGCEpilogueCallback(V8GCController::gcEpilogue);
+    if (RuntimeEnabledFeatures::traceWrappablesEnabled()) {
+        ScriptWrappableVisitor* visitor = new ScriptWrappableVisitor(isolate);
+        isolate->SetEmbedderHeapTracer(visitor);
+    }
 
     v8::Debug::SetLiveEditEnabled(isolate, false);
 
     isolate->SetMicrotasksPolicy(v8::MicrotasksPolicy::kScoped);
 }
 
 namespace {
 
 class ArrayBufferAllocator : public v8::ArrayBuffer::Allocator {
     // Allocate() methods return null to signal allocation failure to V8, which should respond by throwing
@@ skipping 124 matching lines @@
 
     isolate->AddMessageListener(messageHandlerInWorker);
     isolate->SetFatalErrorHandler(reportFatalErrorInWorker);
 
     uint32_t here;
     isolate->SetStackLimit(reinterpret_cast<uintptr_t>(&here - kWorkerMaxStackSize / sizeof(uint32_t*)));
     isolate->SetPromiseRejectCallback(promiseRejectHandlerInWorker);
 }
 
 } // namespace blink