Make it possible for apps that use both WK1 and WK2 to use MessagePorts
The UIProcess-side of WK2 MessagePorts does not actually need to set the shared singleton provider as long as WebCore is updated to rely on it.
Created attachment 332509 [details]
Attachment 332509 [details] did not pass style-queue:
ERROR: Source/WebCore/dom/messageports/MessagePortChannelRegistry.h:38: The parameter name "provider" adds no information, so it should be removed. [readability/parameter_name] 
Total errors found: 1 in 11 files
If any of these errors are false positives, please file a bug against check-webkit-style.
Created attachment 332511 [details]
Comment on attachment 332511 [details]
Clearing flags on attachment: 332511
Committed r227737: <https://trac.webkit.org/changeset/227737>
All reviewed patches have been landed. Closing bug.
Created attachment 332563 [details]
API crash log
This caused the API test: MessagePort.Providers
to fail consistently on iOS Release testers:
I attached the crash log