Introduce infrastructure for tracing ScriptWrappables.

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

Index: third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitor.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitor.cpp b/third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitor.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..32bd0eeb8dadd5333286a69f39cbf80e70dea5a7
--- /dev/null
+++ b/third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitor.cpp
@@ -0,0 +1,60 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "bindings/core/v8/ScriptWrappableVisitor.h"
+
+#include "bindings/core/v8/ScriptWrappable.h"
+#include "bindings/core/v8/ScriptWrappableHeapTracer.h"
+#include "core/dom/NodeRareData.h"
+#include "core/events/EventListenerMap.h"
+#include "core/events/EventTarget.h"
+#include "platform/heap/HeapPage.h"
+
+namespace blink {
+
+bool ScriptWrappableVisitor::isVisited(const void* garbageCollected) const
+{
+    return HeapObjectHeader::fromPayload(garbageCollected)->isDOMMarked();
+}
+
+void ScriptWrappableVisitor::visit(const ScriptWrappable* scriptWrappable) const
+{
+    HeapObjectHeader* header = HeapObjectHeader::fromPayload(scriptWrappable);
+    header->markDOM();
+    m_tracer->AddHeaderToUnmark(header);
+
+    if (scriptWrappable->containsWrapper())
+        scriptWrappable->markWrapperAlive(m_isolate);
+}
+
+void ScriptWrappableVisitor::visit(const void* garbageCollected) const
+{
+    HeapObjectHeader* header = HeapObjectHeader::fromPayload(garbageCollected);
+    header->markDOM();
+    m_tracer->AddHeaderToUnmark(header);
+}
+
+void ScriptWrappableVisitor::visitHandle(v8::Persistent<v8::Object>& handle) const
+{
+    ScriptWrappable::markWrapperAlive(handle, m_isolate);
+}
+
+void ScriptWrappableVisitor::accept(const ScriptWrappable* wrappable) const
+{
+    if (wrappable)
+        wrappable->traceWrappable(this);
+}
+
+void ScriptWrappableVisitor::accept(const ScriptWrappable& wrappable) const
+{
+    accept(&wrappable);
+}
+
+void ScriptWrappableVisitor::accept(const NodeRareData* data) const
+{
+    if (data)
+        data->traceWrappable(this);
+}
+
+} // namespace blink