Stop storing ScriptValue in MessageEvent

third_party/WebKit/Source/core/events/MessageEvent.h

Index: third_party/WebKit/Source/core/events/MessageEvent.h
diff --git a/third_party/WebKit/Source/core/events/MessageEvent.h b/third_party/WebKit/Source/core/events/MessageEvent.h
index 734785f2746a1f6156dc390986b960e4a674c53a..b3759a43b6004d1470595e91d682b7161ffea6b4 100644
--- a/third_party/WebKit/Source/core/events/MessageEvent.h
+++ b/third_party/WebKit/Source/core/events/MessageEvent.h
@@ -31,6 +31,7 @@
 
 #include <memory>
 #include "bindings/core/v8/SerializedScriptValue.h"
+#include "bindings/core/v8/TraceWrapperV8Reference.h"
 #include "core/CoreExport.h"
 #include "core/dom/DOMArrayBuffer.h"
 #include "core/dom/MessagePort.h"
@@ -129,17 +130,14 @@ class CORE_EXPORT MessageEvent final : public Event {
   const AtomicString& InterfaceName() const override;
 
   enum DataType {
-    kDataTypeScriptValue,
+    kDataTypeV8Reference,
     kDataTypeSerializedScriptValue,
     kDataTypeString,
     kDataTypeBlob,
     kDataTypeArrayBuffer
   };
   DataType GetDataType() const { return data_type_; }
-  ScriptValue DataAsScriptValue() const {
-    DCHECK_EQ(data_type_, kDataTypeScriptValue);
-    return data_as_script_value_;
-  }
+  ScriptValue DataAsScriptValue(ScriptState*) const;
   SerializedScriptValue* DataAsSerializedScriptValue() const {
     DCHECK_EQ(data_type_, kDataTypeSerializedScriptValue);
     return data_as_serialized_script_value_.Get();
@@ -166,6 +164,8 @@ class CORE_EXPORT MessageEvent final : public Event {
 
   DECLARE_VIRTUAL_TRACE();
 
+  DECLARE_VIRTUAL_TRACE_WRAPPERS();
+
   WARN_UNUSED_RESULT v8::Local<v8::Object> AssociateWithWrapper(
       v8::Isolate*,
       const WrapperTypeInfo*,
@@ -201,7 +201,7 @@ class CORE_EXPORT MessageEvent final : public Event {
                const String& suborigin);
 
   DataType data_type_;
-  ScriptValue data_as_script_value_;
+  TraceWrapperV8Reference<v8::Value> data_as_v8_value_reference_;

[haraken, 2017/05/02 08:10:14]

In a follow-up CL, I'd prefer introducing:

  WorldAwareV8Reference<v8::Value> ...;

which takes care of all the complexity about the per-world wrappers. Then we can
remove ScriptValue.V8ValueFor().

[bashi, 2017/05/02 08:46:22]

Agreed that we should have such class or mechanism. I'll try to think about it
next week.

   RefPtr<SerializedScriptValue> data_as_serialized_script_value_;
   String data_as_string_;
   Member<Blob> data_as_blob_;