Work In Progress: Handle Maps and Sets in Structured Clone

Source/bindings/core/v8/SerializationTag.h

Index: Source/bindings/core/v8/SerializationTag.h
diff --git a/Source/bindings/core/v8/SerializationTag.h b/Source/bindings/core/v8/SerializationTag.h
index bb0c4eceed003dd687da6690a71203927312a113..12756355d0e1b5288f1eb79fc03c3033da7dcca5 100644
--- a/Source/bindings/core/v8/SerializationTag.h
+++ b/Source/bindings/core/v8/SerializationTag.h
@@ -79,6 +79,10 @@ enum SerializationTag {
     TrueObjectTag = 'y', // new Boolean(true) (ref)
     FalseObjectTag = 'x', // new Boolean(false) (ref)
     CompositorProxyTag = 'C', // elementId:uint64_t, bitfields:uint32_t -> CompositorProxy (ref)
+    MapTag = ':', // length:uint32_t, ???
+    SetTag = ',', // length:uint32_t, ???
+    GenerateFreshMapTag = ';', // ???
+    GenerateFreshSetTag = '\'', // ???
     VersionTag = 0xFF // version:uint32_t -> Uses this as the file version.
 };