Bug 1174624 - Add PortIdentifier copy code in order to communicate with same process. r=baku

dom/base/StructuredCloneHolder.h

@@ -210,7 +210,7 @@ public:
     return Move(mTransferredPorts);
   }
 
-  nsTArray<MessagePortIdentifier>& PortIdentifiers()
+  nsTArray<MessagePortIdentifier>& PortIdentifiers() const
   {
     MOZ_ASSERT(mSupportsTransferring);
     return mPortIdentifiers;
@@ -310,7 +310,7 @@ protected:
   // This array contains the identifiers of the MessagePorts. Based on these we
   // are able to reconnect the new transferred ports with the other
   // MessageChannel ports.
-  nsTArray<MessagePortIdentifier> mPortIdentifiers;
+  mutable nsTArray<MessagePortIdentifier> mPortIdentifiers;
 
 #ifdef DEBUG
   nsCOMPtr<nsIThread> mCreationThread;

dom/ipc/StructuredCloneData.cpp

@@ -41,6 +41,8 @@ StructuredCloneData::Copy(const StructuredCloneData& aData)
     NS_ENSURE_TRUE(mSharedData, false);
   }
 
+  PortIdentifiers().AppendElements(aData.PortIdentifiers());
+
   MOZ_ASSERT(BlobImpls().IsEmpty());
   BlobImpls().AppendElements(aData.BlobImpls());