begin messageport, transferable objects, impl

Accept transfer argument for StructuredCloneData::write

Allow structured clone reads to return a boolean

Add Transferable trait

Add basic skeletons to MessagePort

Implement transfer and transfer-receiving steps on MessagePort

Use transfer and transfer_receive in StructuredClone callbacks

Implement MessageChannel

Freeze the array object for the MessageEvent ports attribute

Implement transfer argument on window.postMessage

Use ReentrantMutex instead for MessagePortInternal

Accept origin as a parameter in dispatch_jsval

Fix BorrowMut crash with pending_port_message

Detach port on closure and check for detached during transfer

Enable webmessaging tests

fix webidl

fix

components/profile_traits/time.rs

@@ -108,6 +108,7 @@ pub enum ProfilerCategory {
     ScriptWorkletEvent = 0x7a,
     ScriptPerformanceEvent = 0x7b,
     ScriptHistoryEvent = 0x7c,
+    ScriptPortMessage = 0x7d,
     TimeToFirstPaint = 0x80,
     TimeToFirstContentfulPaint = 0x81,
     TimeToInteractive = 0x82,