Delete the old WebSocket implementation.

Source/platform/blink_platform.gypi

 {
   'includes': [
     'platform_generated.gypi',
   ],
   'variables': {
     'platform_files': [
       'AsyncFileSystemCallbacks.h',
       'CalculationValue.h',
       'CheckedInt.h',
       'Clock.cpp',
@@ skipping 708 matching lines @@
       'network/HTTPRequest.cpp',
       'network/HTTPRequest.h',
       'network/ParsedContentType.cpp',
       'network/ParsedContentType.h',
       'network/ProxyServer.cpp',
       'network/ProxyServer.h',
       'network/ResourceError.cpp',
       'network/ResourceError.h',
       'network/SocketStreamError.cpp',
       'network/SocketStreamError.h',
-      'network/SocketStreamHandle.cpp',
-      'network/SocketStreamHandle.h',
-      'network/SocketStreamHandleClient.h',
-      'network/SocketStreamHandleInternal.h',
       'network/FormData.cpp',
       'network/FormData.h',
       'network/FormDataBuilder.cpp',
       'network/FormDataBuilder.h',
       'network/ResourceRequest.cpp',
       'network/ResourceRequest.h',
       'network/ResourceResponse.cpp',
       'network/ResourceResponse.h',
       'network/WebSocketHandshakeRequest.cpp',
       'network/WebSocketHandshakeRequest.h',
@@ skipping 214 matching lines @@
       'graphics/ImageFrameGeneratorTest.cpp',
       'graphics/ImageLayerChromiumTest.cpp',
       'graphics/test/MockImageDecoder.h',
       'graphics/test/MockWebGraphicsContext3D.h',
       'image-decoders/gif/GIFImageDecoderTest.cpp',
       'image-decoders/jpeg/JPEGImageDecoderTest.cpp',
       'image-decoders/webp/WEBPImageDecoderTest.cpp',
     ],
   },
 }