[wrapper-tracing] Emite write barrier upon associating a wrapper

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
index 8582768bcd90d4a6267ed15cc8e1bbd68faa232d..d5f791a1388f053fe41f55b8adfeb631bc1bcc30 100644
--- a/third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitor.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitor.cpp
@@ -7,6 +7,7 @@
 #include "bindings/core/v8/ActiveScriptWrappable.h"
 #include "bindings/core/v8/DOMWrapperWorld.h"
 #include "bindings/core/v8/ScopedPersistent.h"
+#include "bindings/core/v8/ScriptWrappable.h"
 #include "bindings/core/v8/ScriptWrappableVisitorVerifier.h"
 #include "bindings/core/v8/V8AbstractEventListener.h"
 #include "bindings/core/v8/WrapperTypeInfo.h"
@@ -237,6 +238,19 @@ void ScriptWrappableVisitor::writeBarrier(
           &(const_cast<TraceWrapperV8Reference<v8::Value>*>(dstObject)->get()));
 }
 
+void ScriptWrappableVisitor::writeBarrier(
+    const void* srcObject,
+    const v8::Persistent<v8::Object>* dstObject) {
+  if (!srcObject || !dstObject || dstObject->IsEmpty()) {
+    return;
+  }
+  if (!HeapObjectHeader::fromPayload(srcObject)->isWrapperHeaderMarked()) {
+    return;
+  }
+  currentVisitor(ThreadState::current()->isolate())
+      ->markWrapper(&(dstObject->As<v8::Value>()));
+}
+
 void ScriptWrappableVisitor::traceWrappers(
     const TraceWrapperV8Reference<v8::Value>& tracedWrapper) const {
   markWrapper(