Delete the old WebSocket implementation.

Source/modules/websockets/WorkerThreadableWebSocketChannel.cpp

Index: Source/modules/websockets/WorkerThreadableWebSocketChannel.cpp
diff --git a/Source/modules/websockets/WorkerThreadableWebSocketChannel.cpp b/Source/modules/websockets/WorkerThreadableWebSocketChannel.cpp
index a49b4ece8fd35fd4258492b46df37722998696b3..8c6fc933067d3dce209b515c2872d609c052ba36 100644
--- a/Source/modules/websockets/WorkerThreadableWebSocketChannel.cpp
+++ b/Source/modules/websockets/WorkerThreadableWebSocketChannel.cpp
@@ -43,9 +43,7 @@
 #include "core/workers/WorkerGlobalScope.h"
 #include "core/workers/WorkerLoaderProxy.h"
 #include "core/workers/WorkerThread.h"
-#include "modules/websockets/MainThreadWebSocketChannel.h"
 #include "modules/websockets/NewWebSocketChannelImpl.h"
-#include "platform/RuntimeEnabledFeatures.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebWaitableEvent.h"
 #include "wtf/ArrayBuffer.h"
@@ -203,11 +201,7 @@ void Peer::initializeInternal(ExecutionContext* context, const String& sourceURL
 {
     ASSERT(isMainThread());
     Document* document = toDocument(context);
-    if (RuntimeEnabledFeatures::experimentalWebSocketEnabled()) {
-        m_mainWebSocketChannel = NewWebSocketChannelImpl::create(document, this, sourceURL, lineNumber);
-    } else {
-        m_mainWebSocketChannel = MainThreadWebSocketChannel::create(document, this, sourceURL, lineNumber);
-    }
+    m_mainWebSocketChannel = NewWebSocketChannelImpl::create(document, this, sourceURL, lineNumber);
     m_syncHelper->signalWorkerThread();
 }